Cylinder 4 misfire

[overst33r]

My parent's 2002 Impala threw a misfire code for cylinder 4. It recently had some work done to it.

The spark plugs/wires were changed, and the harmonic balancer pulley was changed.

I checked the connections on all wires and they were not loose/dirty etc.

The work was done about a month ago, but the check engine light came on just yesterday.

As I was on my way to autozone to read the code, I drove the car a bit spiritedly because my parents don't. The check engine light went away...

Should I just run some fuel system cleaner through it? It makes me think it's the injectors because the light went away after I drove it.

 

[HannibalX]

Bad COP is my guess.

 

[Vette73]

swap the plug from 4 to another cyl. Then check the wire to make sure it is not cut/leaking.

If after that it is still cyl 4 then replace the coil.

 

[exdeath]

Nothing to do with the fuel system. Misfire is an ignition problem logged when the computer doesn't get a confirmation of coil field collapse from the ignition module or when the computer doesn't see an RPM increase during an ignition event.

As above, swap coils and see if the problem follows the coil. Pretty sure that model uses a "wasted spark" system with 3 external coil packs feeding 3 pairs of cylinders, so you'll need to swap the low voltage connectors at the base of the coils coming from the ignition module as well to keep the cylinder pairs together. Though it might all be integrated with one connector as one unit, and you might have to swap the coil packs themselves on a distribution rail.

 

[Bignate603]

Originally posted by: exdeath
Nothing to do with the fuel system. Misfire is an ignition problem logged when the computer doesn't get a confirmation of coil field collapse from the ignition module or when the computer doesn't see an RPM increase during an ignition event.

Sorry but this isn't correct. Clogged fuel injectors can cause engine misfires. You're right it could be an ignition problem but a dirty fuel system could explain it also. I'd do what others have suggested about swapping the plug on the 4th cylinder to another and see if that makes it switch cylinders. If that doesn't solve it you have a bad coil or a clogged injector. I personally don't put a huge amount of faith in those bottles of injector cleaner but I've had good results from my mechanic doing an on car cleaning (running solvent through the fuel rail). It smoothed up the idle on our van and the misfire that we were having went away.

 

[dmh1167]

Hi all you guys all have some pretty good answers to this issue but before swapping the plug pull it read it and find out what joe mechanic put in if its a cheapo you just found the problem.

Alot of GM'S use OE irridium plugs at 8 to 12 dollars each a tune up special doesnt cover 120 dollars in plugs and I've seen this more than once running shop. Dealers and good shops have been caught using cheaper plugs that have the right thread pitch throw and heat range and wrong electrode they go toast quick. There is so much juice going through the secondary that its happy to take a shortcut. Platinum plugs dont usually run long in a machine that came with irridium ngk v power gets ya 20k before they are shot. Good luck hope this helps.

 

[RU482]

pretty sure an 02 bread and butter 3.4 or 3.8 would have Platinum plugs at best from the factory

 

[Bignate603]

Originally posted by: RU482
pretty sure an 02 bread and butter 3.4 or 3.8 would have Platinum plugs at best from the factory

This. Platinum plugs don't make the car run any different, the advantage is they last for much longer. Copper plugs arguably work better in a performance applications but they need to be replaced more often. For normal cars, especially ones that have plugs in places that are hard to replace (like many FWD V6 vehicles) the long replacement intervals is a very large advantage so you see them in many vehicles.

 

[dmh1167]

The factory numbers for the plugs in the impala have been supeceded with the irridium numbers but a miss fire usually 9 out of 10 times is centered around a poorly performing plug or a bad wire usually killed by the tech changing the plug.

not reapplying dielctric grease to the wire before reinstall will make sure the wire dies on next plug change. Go to sparkplugs.com they have a wealth of info not to be taken for granted on sparkplugs to check missfire here is a simple cheap idea if you dont have a code reader or scan tool ect. open hood at night and watch for sparks. If you see em coming out of wire might be wires are bad. Codes and computers are great but nothing is better than the best computer made the one in your head.

 

[Zenmervolt]

Originally posted by: dmh1167
Hi all you guys all have some pretty good answers to this issue but before swapping the plug pull it read it and find out what joe mechanic put in if its a cheapo you just found the problem.

Alot of GM'S use OE irridium plugs at 8 to 12 dollars each a tune up special doesnt cover 120 dollars in plugs and I've seen this more than once running shop. Dealers and good shops have been caught using cheaper plugs that have the right thread pitch throw and heat range and wrong electrode they go toast quick. There is so much juice going through the secondary that its happy to take a shortcut. Platinum plugs dont usually run long in a machine that came with irridium ngk v power gets ya 20k before they are shot. Good luck hope this helps.

What the hell?

Wrong so many ways that I'm having trouble figuring out where to start.

Iridium plugs do not carry any more "juice" than platinum or even copper plugs. In fact, Iridium plugs require less voltage to create a spark.

Iridium plugs are used in OE applications because the last longer, not for performance gains. In fact, people looking for performance gains often switch back to copper plugs which do perform better, especially in engines using forced induction. The downside to copper plugs is that they wear out faster (20,000-30,000 miles at most, people generally replace them at 15,000 miles).

The move to platinum (and now to iridium) is strictly to allow the manufacturer to lengthen service intervals, not for any meaningful performance gain. Systems originally-equipped with iridium plugs may not supply enough current to reliably fire copper plugs, but they certainly will not make the copper plugs "go toast".

ZV

 

[Zenmervolt]

Originally posted by: dmh1167
The factory numbers for the plugs in the impala have been supeceded with the irridium numbers but a miss fire usually 9 out of 10 times is centered around a poorly performing plug or a bad wire usually killed by the tech changing the plug.

not reapplying dielctric grease to the wire before reinstall will make sure the wire dies on next plug change. Go to sparkplugs.com they have a wealth of info not to be taken for granted on sparkplugs to check missfire here is a simple cheap idea if you dont have a code reader or scan tool ect. open hood at night and watch for sparks. If you see em coming out of wire might be wires are bad. Codes and computers are great but nothing is better than the best computer made the one in your head.

Once again, no.

I have never bothered with using dielectric grease on my plugs and I have never had a plug wire's connector "die".

To the OP: Occasionally carbon build-up can cause spark-knock or other misfire-type of issues. An "Italian tune-up" (running the engine hard up to redline a few times) can sometimes fix that. My father's old Explorer was that way, every couple of weeks he had to get on it hard or it would start spark-knocking when using regular fuel (owner's manual spec-ed regular). Diving it hard would burn off the carbon and it would be fine again.

I would remove the plugs and check on them (at the very least I'd check the plug in the affected cylinder) just to be sure that it looked OK. If the car is close to 100,000 miles, it's time to consider replacing the plugs anyway.

ZV

 

[dmh1167]

Wrong Wrong Wrong The boot on the wire welds to the plug the grease allows for removal also wrong copper plugs under todays hi output ignition systems go bye bye really quick so if you have autolights falling out of your pockets run them change them once a month and be happy for the rest of us we should use quality not fishing weights. Oh and if you dont use dielectric keep new wires and an ohm meter on hand to test the ones you destroy ripping out.

The spark loves to jump from sharp edge on new plug as the edge goes away so does performance a larger gap gives hotter spark but works coil harder, as far as a debate on the subject pointless got enough certs and degrees to wallpaper a wall and when talking to some folks the contempt oozeses off them

statements like my cousin billybob fixes lawnmowers he knows what he doin and he says this.Big deal who cares Id bet money mariok parents issue is the wire "most likely" or the plug let us know it would be good to hear.

 

[Bignate603]

Originally posted by: dmh1167
Wrong Wrong Wrong The boot on the wire welds to the plug the grease allows for removal also wrong copper plugs under todays hi output ignition systems go bye bye really quick so if you have autolights falling out of your pockets run them change them once a month and be happy for the rest of us we should use quality not fishing weights. Oh and if you dont use dielectric keep new wires and an ohm meter on hand to test the ones you destroy ripping out.

The spark loves to jump from sharp edge on new plug as the edge goes away so does performance a larger gap gives hotter spark but works coil harder, as far as a debate on the subject pointless got enough certs and degrees to wallpaper a wall and when talking to some folks the contempt oozeses off them

statements like my cousin billybob fixes lawnmowers he knows what he doin and he says this.Big deal who cares Id bet money mariok parents issue is the wire "most likely" or the plug let us know it would be good to hear.

Ok, you're much more condescending than anyone else in this thread and you're also almost impossible to understand. If you replied in understandable sentences people might listen. Right now you sound like billybob, the lawnmower mechanic.

Yes, sometimes the wire sticks, but I've never had a wire get torn up. Anyways, if you're running plugs that go 100k you should be replacing the wires every single plug change. The real reason to use the grease is to keep moisture out of the connection so it doesn't corrode. Copper plugs DO make a better spark for high performance applications. It's a KNOWN issue that they don't last as long. Some people are fine with that. Others aren't. If you're doing one of those cheap tune up specials of course they're going to use the cheapest plugs they can find. They aren't going to be paying $10 a plug when they're only charging $100 for the tune up. It's your car, you've got to ask what they'll be putting in it. If you don't its your fault.

 

[Zenmervolt]

Originally posted by: dmh1167
Wrong Wrong Wrong The boot on the wire welds to the plug the grease allows for removal also wrong copper plugs under todays hi output ignition systems go bye bye really quick so if you have autolights falling out of your pockets run them change them once a month and be happy for the rest of us we should use quality not fishing weights. Oh and if you dont use dielectric keep new wires and an ohm meter on hand to test the ones you destroy ripping out.

The spark loves to jump from sharp edge on new plug as the edge goes away so does performance a larger gap gives hotter spark but works coil harder, as far as a debate on the subject pointless got enough certs and degrees to wallpaper a wall and when talking to some folks the contempt oozeses off them

statements like my cousin billybob fixes lawnmowers he knows what he doin and he says this.Big deal who cares Id bet money mariok parents issue is the wire "most likely" or the plug let us know it would be good to hear.

Gee, I guess my many years of experience working on old cars isn't worth as much as your inability to construct a coherent sentence.

The bottom line here is that you are flat wrong.

Platinum and Iridium plugs require lower voltage to generate a spark, not higher. They are not used for performance gains, only for longevity gains. People running high-performance ignition systems prefer copper plugs. High-output ignitions do not make copper plugs "go bye bye really quick". A copper plug is only good for about 15,000 miles regardless. It has nothing to do with "quality". I change the NGK BPR7ES plugs in my 951 every 15,000 miles, hardly "once a month". The engine has melted platinums but the copper plugs hold up just fine.

As far as your ridiculous claims about the wire ends somehow "welding" to the plugs all I can say is that I have never had such a thing happen to any of the old cars I've worked on. Never. I have, however, seen idiots who grip the wire instead of the connector ruin plug wires and then try to blame their own mistake on a lack of dielectric grease.

The OP's issue is unlikely to be the wire since there shouldn't have been anyone messing with it. Chances are that it was a transient event and not recurring (since the light turned itself off) which would indicate a one-time misfire that was cleared up after some spirited driving. He should still check the suspect plug to determine its condition, and if he's near 100,000 miles it's time to change the plugs and wires anyway, but if the light turned itself off, it is unlikely that the initial issue is a persistent event.

ZV

 

[dmh1167]

For not being able to understand my incoherant sentences you sure work hard at a rebuttle. Anyhow he said his parents had the secondary ignition serviced new plugs and wires I realize I misspoke it is more than likely the plugs are cheapo willy bob specials.

Second the plug boots on alot of late model cars will stick like glue to the plug even a decent tool for pulling the boot isnt enough on hi mileage engines to remove them without damage dielectric does stop corrision and also aids in later removal of the wire.

Most important to note, could care less about slants form perfect strangers that are as easy to ignore for good as a mouse click. By the way I love using NGK V POWER plugs , every time I get the chance but in late model apps that require a hier quality plug the performance slopes off too quick. In town driving spanks the poor things they foul and after that you get repeating check engine lights even after running hi rpm freeway driving ect.

 

[Zenmervolt]

Originally posted by: dmh1167
For not being able to understand my incoherant sentences you sure work hard at a rebuttle. Anyhow he said his parents had the secondary ignition serviced new plugs and wires I realize I misspoke it is more than likely the plugs are cheapo willy bob specials.

Second the plug boots on alot of late model cars will stick like glue to the plug even a decent tool for pulling the boot isnt enough on hi mileage engines to remove them without damage dielectric does stop corrision and also aids in later removal of the wire.

Most important to note, could care less about slants form perfect strangers that are as easy to ignore for good as a mouse click. By the way I love using NGK V POWER plugs , every time I get the chance but in late model apps that require a hier quality plug the performance slopes off too quick. In town driving spanks the poor things they foul and after that you get repeating check engine lights even after running hi rpm freeway driving ect.

BPR7ES plugs are standard copper. That's not a V-Power part number and anyone with a decent amount of experience ought to know that.

Do I really have to mention, for the third time, that platinum and Iridium plugs require lower voltage to generate a spark, not higher? This invalidates your ridiculous misconception that modern ignition systems will "spank" copper plugs.

If you are experiencing fouling, the plugs are too cold for the engine; the fault lies with you for selecting an inappropriate plug, not with the plugs themselves. Either that, or the EFI is malfunctioning and running excessively rich.

I'll say this very plainly for anyone else in this thread: You only know enough to get yourself into trouble and not enough to help others out. If you really think that Iridium and Platinum plugs are higher quality, then all it means is that you don't know enough to sift through marketing claims.

ZV

 

[MovingTarget]

Update? Is the problem fixed?

/curious about the final verdict

 

[Bignate603]

Originally posted by: Zenmervolt
I'll say this very plainly for anyone else in this thread: You only know enough to get yourself into trouble and not enough to help others out. If you really think that Iridium and Platinum plugs are higher quality, then all it means is that you don't know enough to sift through marketing claims.

ZV

Eh, the platinum plugs have their place. On my van the plugs on the firewall side of the engine are such a pain to replace I put platinum plugs on just so I don't have to deal with it for another 100,000. It's more about convenience for that vehicle than anything else.

 

[dmh1167]

I know your bpr7es foul o matic plugs arent v power , v powers cost more , if you run an old Ford with a distributor sure put in whatever floats your boat ,

Chevy HEI and newer DIS systems put out a potential of 100k to 200k volts at 2 to 16 AMPS aww heck you already know all that why dont ya pull a wire while its running I ve seen a little contempt go along way. Clear across the shop when Joe know it all pulls a wire on hei or dis while its runing.

Humm if you know so mutch could you explain to dumb know nothing me about ignition coil turns ratio, why most of todays wires are 8mm plus and the product of bore times bore times stroke times Pi times number of cylinders.

Let me guess you dont put anti seize on plugs either its just there to stop corrision toh wait, we will have another weak comment if I dont specify spark plugs that are going into aluminum heads get anti seize.

 

[MikeMike]

dmh, you MIGHT have a little bit better if you could spell, could produce proper sentences, spacing, periods, etc.. But no you havent.

 

[LTC8K6]

200,000V X 16A = 3,200,000 watts.

That's impressive!

 

[Bignate603]

Originally posted by: LTC8K6
200,000V X 16A = 3,200,000 watts.

That's impressive!

Let's do some math based on DMH's numbers...
Someone please double check my math.

8 cylinder engine
4000 rpm
1.5 millisecond (4.16E-7 hr) spark plug duration (sourced from this book)
Sparks/hour = min/hr*rpm*# of cylinders/2 = 960000 sparks per hour
(the number is divided by two because its a 4 stroke and any given cylinder only fires every once per two rotations of the crank)
Total time of spark over 1 hour = sparks/hour*spark duration (in hours) = .4
Total amount of energy used over hour to power spark plugs = 3,200,000 watts*.4 = 1,280,000 MWh per hour of running.

For comparison that's roughly the amount of energy in 35,000 gallons of gas.

 

[overst33r]

Originally posted by: MovingTarget
Update? Is the problem fixed?

/curious about the final verdict

I cleared the CEL and drove it hard a bit and it hasn't come back.

 

[Bignate603]

Originally posted by: mariok2006

Originally posted by: MovingTarget
Update? Is the problem fixed?

/curious about the final verdict

I cleared the CEL and drove it hard a bit and it hasn't come back.

That's good to hear. Keep watching it but it could have just been a random thing.

 

[Zenmervolt]

Originally posted by: dmh1167
I know your bpr7es foul o matic plugs arent v power , v powers cost more , if you run an old Ford with a distributor sure put in whatever floats your boat ,

Chevy HEI and newer DIS systems put out a potential of 100k to 200k volts at 2 to 16 AMPS aww heck you already know all that why dont ya pull a wire while its running I ve seen a little contempt go along way. Clear across the shop when Joe know it all pulls a wire on hei or dis while its runing.

Humm if you know so mutch could you explain to dumb know nothing me about ignition coil turns ratio, why most of todays wires are 8mm plus and the product of bore times bore times stroke times Pi times number of cylinders.

Let me guess you dont put anti seize on plugs either its just there to stop corrision toh wait, we will have another weak comment if I dont specify spark plugs that are going into aluminum heads get anti seize.

*tosses dmh a shovel*

Keep digging buddy-boy.

ZV