Check engine light question

[NuroMancer]

So,
Besides taking it to a local VW guy or the stealership, I first thought I'd get some advice from the Garage crowd. My car is a 2004 GTI 1.8T. All major service jobs have been done at my local VW shop. The car has 66,XXX km on it and I keep her in great shape.

Last night on my way home I was merging onto the freeway and accelerating out of the curve. At the height of the RPM guage in Second gear, it seemed like the car hesitated or lost a little bit of power at like 5100 ish out of 6000. As this happened the check engine light flickered, and then turned on. Just to clarify, it wasn’t at all like a clutch letting go, it just almost like sputtered?

So, out of curiosity I brought the car up to the same rpm band slowly instead of basically floored and the same thing does not occur (in second gear). Not being a huge car guy/mechanic, but knowing a little, I immediately have a few things that came to my mind, but they are just complete guesses. Anyway, I was just a few km’s from home so I continued, and parked it for the night so there she sits, didn’t have a chance to peak at it this morning.

Thoughts? Questions?

Jon

 

[BW86]

Probably a misfire. If you were in my area I could scan your car with vag-com

 

[NuroMancer]

If I just had my water pump done, and a timing chain etc is it possible they replaced my PCV valve?

 

[NuroMancer]

I am not a mechanic, so forgive my ignorance

I was reading up more on the internet on misfires, and I noticed this.

"A rough idle or stalling. A large vacuum leak can lean the air/fuel mixture out to such an extent that an engine will not idle at all. An EGR valve that is stuck open at idle can have the same effect as a vacuum leak. So too can a loose positive crankcase ventilation (PCV) hose, a leaky PCV valve or the wrong PCV valve (one that flows too much air for the application). If somebody replaced the PCV valve recently, they may have installed the wrong PCV valve. The rough idle in all of these cases is caused by "lean misfire." The fuel mixture is too lean to ignite reliably so it often misfires and fails to ignite at all. Lean misfire will show up as elevated hydrocarbon (HC) readings in the exhaust, which may be enough to cause a vehicle to fail an emissions test. "

I have noticed that since I had the work done, that I have a bit of a rougher idle, I was going to address it at the next oil change as I didn't connect the dots.

So. Is it possible they introduced a vacumm leak or an issue with my PCV value when they did the last work on the car?

 

[bruceb]

When the Check Engine Light just blinks at you a few times, it has detected a misfire condition. Start with the basics .. New Spark Plugs & Plug Wires and if your car uses a distributor, a new cap and rotor. Be very careful not to crack the new spark plugs. It only takes a hairline crack, which you might not even notice, to cause a misfire. Odds are, you are on your original set of Plugs & Wires

 

[Lotheron]

If I just had my water pump done, and a timing chain etc is it possible they replaced my PCV valve?

Since it's a part that they'll likely charge you for, it should show up as a line item on your invoice.

Also, if you goto Autozone they'll pull your code for free, although as stated earlier, it's probably a misfire code. It could pull something else such as an O2 sensor though.

 

[Vetterin]

You will feel a different idle if the timing chain was not installed correctly.

 

[StageLeft]

As said, get the code pulled. My money is on it being C004 which will read as "volkswagen".

 

[BW86]

Most misfire codes wont show up on a code reader if they're intermittent

 

[Lotheron]

Most misfire codes wont show up on a code reader if they're intermittent

If it throws a CEL that stays on it should show up on a reader as a stored code.

 

[BW86]

I had the same problem and my code reader wouldnt pick it up. I had to get VAG-COM software to get the code. But yeah if the CEL stays on a code reader should pick it up.

 

[nakedfrog]

Is that one of the year models that was prone to the coil pack developing cracks?

 

[NuroMancer]

Is that one of the year models that was prone to the coil pack developing cracks?

Had me wondering for a second, so I looked it up.

24v VR6 and all 1.8t's
-Issue
VW has had serious problems with its individual (coil-on-plug) ignitions. For whatever reason, the actual coils (the little boxes on top of your spark plugs), died, and died frequently. This causes loss of power, misfires, crappy throttle response, etc.

-Symptoms
Check engine lights, power loss, complete engine shutdown, misfires, basically you should check your coilpacks (if they have not been replaced) anytime you have engine problems.

-Diagnosis
A scan of the engine codes by the dealer, a friend, or someplace that does it for free can give you insight into the problem. Anything relating to misfires or the ignition system can probably be attributed to the coils. Many times the car will not be able to be driven at all, in this case your best bet is to just have it towed to the dealer. Users in the 1.8t forum and the 24v Vr6 forum are particularly adept at diagnosing coil pack related problems.

-Is VW aware?
Yes they are, and they have issued a recall. At this point in time the earlier supply issues are gone, and your dealer should have plenty of the revised coils in stock. It seems that the newer cars (late 2003's and later) have received the new packs during manufacture, and therefore are not affected (although that is not a rule). Contact your dealer if you think you have coil pack problems. In addition, at this point most dealers will replace all the packs if one goes out and they are an earlier revision.
Edit: Stolen from Vwvortex forums.


Basically, I need a scan as everyone has said, and I will do that this weekend.
Luckily we bought one of my buddies a Vag com for his birthday 2 years ago, so now I can use it!

 

[NuroMancer]

So, In my brilliance, I forgot to email myself the codes to work.

I ran a scan on the car Sunday night with a Vag-com.

Came back with two errors, now I'm not going to get them exactly right, but this is from memory I will update with the exact codes tonight.

1. Random/Multiple misfires.
2. Misfire cylinder #4

After making a copy of the output I cleared the codes, and took the car for a short drive.
Nothing came up during the drive, but I did not replicate the originial conditions either (full throttle at the top of 2nd gear.)

So my layman interpretation of the results is that I should replace the wires and spark plugs on the motor? I'm the second owner, but afaik the plugs have never been done (only 66,XXX Km on the car). Should I also replace the cap and rotor as one of the guys suggested?

 

[BW86]

If it happens again, swap coilpacks and see if the misfire follows. But If I were you I would replace the spark plugs if you haven't done them since you got the car and make sure you gap them properly.

 

[nakedfrog]

What were the weather conditions like when the issue first manifested itself? Rainy, foggy, anything like that?

 

[lavaheadache]

As a fellow mk4 Gti owner with lots of hours under the hood of my car I can tell you this with confidence....... COILS!!!!! Just change the one/ones that are faulty and you'll be good to go. Don't worry about $$$$, on the 1.8t they are really cheap. Vr6 on the other hand $500-$600