Rough Idle, stumbling

[cayenneturbo]

I have had my 04 CTT for 4 days and 1000 miles, 800 of which was driven back from dealership. Car checked out ok there and drove great down here. On my way to work this morning the car was really running rough at Idle, every so oftent it would really shake etc. During driving no issues, but then again during lunch I started it up and it was ok for a few then rough all over again. The coils were replaced by dealer in 4/08 and 10k ago. It has 51K on it now. Any ideas, sounds like a miss fire, but no CEL or engine codes pulled via my handheld OBDII generic scanner.

I have an appt tomorrow at local dealership, I am hoping not to get raped. I am trying to prepare for worst.

Thanks

[Hudnu46]

Porsche cars/SUV's like to be driven, if the car had been sitting for a while or "driven on weekends and to the grocery store once a week" more than likely all you need to do is go out on your own and open'er up for a good stretch... Safely of course. More than likely that's all the dealership is going to do, especially if you are not getting any codes or faults.

[wvicary]

Does the fault occur with the A/C on or off? If it was a misfire the check engine light would be on straight away. It's recommended to replace the spark plugs with the coils.

[cayenneturbo]

No fault codes or CEL, I have a standard OBD II scanner and I am getting no error codes. It is really rough, it will be normal than a big stutter/shake. When stepping on the gas the car does the same ,,, major vibration, stutter. I am taking it to the dealership in the morning. I called the previous dealer and received all the work completed on it, all coils and plugs replased under 10k /1 yr ago. I hope it is just that, a cracked coil.

[shnikus]

FWIW Looking at the records of my 05 CTT the coils were replaced twice during 2008 (by previous owners). So I assume that it is possible you have a cracked coil again.

I called the previous dealer and received all the work completed on it, all coils and plugs replased under 10k /1 yr ago. I hope it is just that, a cracked coil.

[cayenneturbo]

FWIW Looking at the records of my 05 CTT the coils were replaced twice during 2008 (by previous owners). So I assume that it is possible you have a cracked coil again.

I called the previous dealer and received all the work completed on it, all coils and plugs replased under 10k /1 yr ago. I hope it is just that, a cracked coil.

So I took to Porsche Dealership here in Phoenix and it turns out that #2 plug had water inside and its coil was cracked . All other coils were good. So all 8 plugs changed and the one coil. So a $500 tune up because in the infinate wisdomw of the dealership in Colorado (non porsche) they had the engine pressure washed.

I called them to complain about a repair caused by them, they called my dealership for a dealer to dealer price adjustment and he was going to get with thier boss and get back to me. My thing is if they asked for the dealer price they would have just covered it vs having to reimburse me for the actual price. It is BS that I had to spend $500 for thier mistake.

I also had them update the DME to current software and do a complete check of car.

The car runs great in all gears now, but it still has some vibration at idle.... not completely smooth although I gather from threads that this is inhierent to the model.

I hope the dealer comes through and reimburses at least part of my cost.

[wvicary]

It's very odd with a misfire that you didn't get a check engine light or a code set.

[zgdanska]

how is it working now with new plugs and coils ? I have the same problem

[cayenneturbo]

how is it working now with new plugs and coils ? I have the same problem

It works great, no issues at all