Between 60k and 97k the check engine light has come on numerous times. Each time it has been misfire #, I replace the coil pack in question and the problem goes away, I have done this 6 times, its always a different cylinder.
The last time was about 2 1/2 months ago, the car has been running fine since then, so my daughter went into labor Friday, which for us was about a 6 hour drive, about 4 hours into the drive we stopped at a rest area and when we started the car it was spitting and sputtering like it always does. The nearest dealer to buy a new coil pack was over 100 miles away, rather than be stranded we drove the 100 or so miles with it running like crap. This morning it was time to go home so we drove to the dealer I bought a new coil pack, installed it in the parking lot...problem went away.
Again 4 hours into the 6 hour road trip we stopped at a gas station..and bingo check engine light comes on and the car runs like crap again. scan tool shows # 3 misfire this time.
At $80 a piece I can't afford to keep buying coil packs.
From the sounds of it, I doubt its the coil packs - If it is keep in mind parts should have at least a 1 year warranty. You mention having a misfire come up on the scan tool - can you give us a DTC please? Im assuming its P0303?
I have had the same problem, but this was from moisture shorting the spark plug before it had a chance to fire. Try pulling all the coils, have a look to see if there is any debris or moisture build up. Also inspect the coil itself. The shaft (not sure of the actual term) between the coil and spark plug can disconnect from the coil the same way it disconnects from the plugs. Disconnect it and inspect these inside and out for any oil or other contaminants. If you dont already, reconnect them with a little dielectric grease, it promotes conductivity between components.
Next pull the plugs themselves, check the condition because these can sometimes give you a hint, for example if its running too lean.
If all these check out fine and your plugs seem normal, my guess would be a computer problem in the ECM. A new one will cost you about $600, but if your going to buy one its probably worth your wile to get it diagnosed by a shop and spend a few extra hundred on labour just to make sure. Nothing worse then dropping a lot of cash just to find out it didnt do anything.
Its for sure the coil pack, after limping the car home yesterday I put the scan tool on it again, Misfire # 1 (the new one I just bought), I cleared the codes, switched the coil pack with # 2 and now it says misfire # 2.
I even put the original back in from 2 days ago, same same, misfire # 1, or 2 depending on where I put it.
I have no idea what to do, I cant take the coil pack where I got it, 200 miles away.
Looks like I am stuck buying another coil pack...this will be # 8 in a 6 banger.
When your check engine light comes on, does it flash or stay constant? And also what codes are coming up on your scan tool? As far as the latest faulty coil - why dont you go out and buy the replacement, then a few days later return the faulty one to the dealership nearby using the new receipt? They wont know the difference unless the individual part number is quoted, and even then you can always argue you are a loyal customer (7 coil packs) and you purchased that one from a dealership 200 miles away. If they have any sense customer loyalty wise they will refund you, even if its just store credit.
So anyway, if it is the coils I would imagine something on the vehicle is the culprit still, and the coil packs are merely the symptom. My reasoning is that I cant imagine multiple packs over a 200+ mile radius all being defective, it just seems too weird. If you can give me the DTC's that you get on your scan tool it might shed more light, but right now Im as confused as you are. Also, which packs are the ones that go, the new ones, old ones, or just randomly? Is it limited to any cylinder(s), are there any that repeat more frequently, etc?
I took a quick look around and found this:
"Re: Cause of coilpack failure
Most common cause of failure for coils (COP or single) would be stressing the coil asking for too much spark voltage. That means, plugs gone bad, or gap is too large for too long, boot is ripped, bad ECU output or ICM, etc, etc.
If the coil needs to increase the output too much for too long this generates too much heat and will cause it to weaken or eventually just fail and even explode/break open the coil."
In this case, the gap was set too large. Try checking your plugs, the gap should be 0.031" or 0.8mm. If your plugs are properly gaped, and everything else seems fine I would suggest taking it to the dealer and have them run diagnostics on the ECM.
Thanks for taking the time to research this.
A little while ago I switched out the new (non working) coil for the old one and still got misfire #1, I put the new one back and same thing. For the heck of it I took the spark plug out of #1 and put it in #2, now I am getting misfire #2.
As you found in your research, this very well could be my spark plugs, I'm going to change them out in a little bit, I'll post what the results are.
Did you ever find the cause of this? I am going through the same thing. I have had 5 or 6 replaced. Now the light is on again, p0305 and i replaced coil #5 and it's still bad. I had a complete tune up done a couple years ago and have only put maybe 10,000 miles if that on my car in the past 2 years.
Just a quick update to this, I haven't had a problem with coil packs since I replaced the coil packs.
I happened to be at the junkyard and found a verona, I pulled all the coil packs out, bought all 6 for $20, heck of alot better then $80 for 1 new one.
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