Saturn ION Engine

steelodon

Senior member
Oct 29, 2007
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I have a Saturn ION engine that appears to stagger or knock when idle. When I give it gas, the knocking appears to stop. I look at the engine cover and there is vibration. Any suggestions?
 

phucheneh

Diamond Member
Jun 30, 2012
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I can't really say I know what 'stagger or knock' means in this context. 'Stumble' is a common word, but it's usually describing an engine that hesitates or wants to die, usually in response to throttle input.

It sounds to me like you have a misfire. Assumably a mild one (i.e. there is not a cylinder that is entirely worthless), which is why it appears to stop (it doesn't, it's just less noticeable).

That or it's just idling too low.

Check engine light on? Does the car have a tachometer? If so, what's the idle speed, and how much does it vary?
 

steelodon

Senior member
Oct 29, 2007
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The Check Engine light is on. The RPMs seem to be under 1000 or so. I'll have to check again to confirm.
 

SparkyJJO

Lifer
May 16, 2002
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Any time the check engine light is on it is always a good idea to get it scanned. Go to Autozone, get it checked, then report back with the code number.

There are about eleventymillion things that could all contribute to what you're experiencing, ranging from minor to catastrophic. So, yeah, the code would help narrow it down ;)

Also, the year and miles would be good info as well.
 

phucheneh

Diamond Member
Jun 30, 2012
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Frankly, it baffles me when someone tries to describe a car problem, and never thinks to mention something like the CEL being on.

Think of your car as a kid with a learning disability. And he left you a note before disappearing.

Yeah, the note he left is probably cryptic and vague, but I bet you'd see what it said before you just started wandering through the woods yelling his name.
 

phucheneh

Diamond Member
Jun 30, 2012
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It is a 2005 Saturn ION that has about 141,000 miles on it.

Go to Autozone/Advance/ect and ask them to read the DTC's. Ignore any advice they to attempt to give you, say thanks, and report back here with the codes. They will be in the format of 'Pxxxx' where each 'x' is a number. First one is usually 0, which means it's a universal code. 1 means manufacturer-specific.
 

steelodon

Senior member
Oct 29, 2007
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Received a code P0302 from a scanner loaned to me. Did a rescan and the code did not appear again.
 

Zenmervolt

Elite member
Oct 22, 2000
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Received a code P0302 from a scanner loaned to me. Did a rescan and the code did not appear again.

That's a code for a Cylinder #2 misfire.

The fact that the light hasn't come back just means that the misfire is transient. Chances are that in a couple hundred miles the light will come back.

If you've never changed the spark plugs, start with that.

ZV
 

steelodon

Senior member
Oct 29, 2007
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That's a code for a Cylinder #2 misfire.

The fact that the light hasn't come back just means that the misfire is transient. Chances are that in a couple hundred miles the light will come back.

If you've never changed the spark plugs, start with that.

ZV

The Check Engine light was flashing on acceleration
 

phucheneh

Diamond Member
Jun 30, 2012
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The Check Engine light was flashing on acceleration

That would be the 'stop driving' light. A flashing CEL is indicative of serious misfiring (and catalyst damage).

The code will come back; GM is just awful at setting misfire codes in a timely fashion.

Change spark plugs (it's very fast and cheap). If that does not help, and the misfire continues to be only on #2, swap ignition coils between it and another cylinder and see if the misfire moves with it.

You also try just swapping plugs, but they're cheap enough that you might as well just go ahead and replace them. Also Delco plugs blow.
 

phucheneh

Diamond Member
Jun 30, 2012
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Would that cause the front transmission mount to rock?

Per every revolution of the crankshaft, your engine fires two cylinders.

If you have a dead miss on one, that means on every other crank revolution, there's going to be a big awkward hole. It's not going to be pleasant, and yes, it will result in very rough and vibration-heavy operation.

You may want to take this to someone. You're going to end up trashing your catalytic converter(s) and possibly your engine over a problem that can probably be fixed for well under a hundred bucks in parts.
 

steelodon

Senior member
Oct 29, 2007
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Per every revolution of the crankshaft, your engine fires two cylinders.

If you have a dead miss on one, that means on every other crank revolution, there's going to be a big awkward hole. It's not going to be pleasant, and yes, it will result in very rough and vibration-heavy operation.

You may want to take this to someone. You're going to end up trashing your catalytic converter(s) and possibly your engine over a problem that can probably be fixed for well under a hundred bucks in parts.

Someone is going to pick it up tomorrow.
 

phucheneh

Diamond Member
Jun 30, 2012
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You don't have any wires. That car has one of three things- all four coils built into an assembly (I think this is just Aveos), four individual coils, or two coils built into an assembly ('waste spark,' coils fire twice as often). All three designs sit right on top of the plug and AFAIK nothing else is serviceable except the spark plugs (and the boots, I guess).

Probably needed the coil (and has the 'assembly'), so coil + plugs is a good repair. I just hope they didn't charge you a random 30-50 bucks for nonexistent plug wires.