: 2004 CTS 3.6L rough idle



times1
04-25-04, 10:23 PM
My 2004 3.6L (1SC) has random vibration (lumps) during idle, worse during cold start. VIN# ... 40112860. Dealer CND my first complaint at 3K miles. I test drove a new 3.6L 1SC CTS at another dealer, no lumps, no vibration at idle. Took it back in at 7K miles with same complaint. Tech acknowledged the problem and supposedly "reprogrammed PCM". Car still idles rough, randomly vibrates noticeably. What do you suggest as a next step?

Speedingpenguin
05-05-04, 03:51 PM
Perhapps its the IAC valve?

JoeCaddy1
05-07-04, 08:41 PM
The 3.6L does not have an IAC valve. It controls air via the electronic throttle. There should be a service bulletin on rough idle. There was a calibration change after start of production to address this issue.

times1
05-11-04, 08:04 AM
Dealer perfomred the calibration change (ECM update). Rough idle continues, cold or hot, doesn't matter. :banghead:Already contacted Cadillac Customer Service. Any other suggestions?

Devil_concours
05-20-04, 03:58 AM
i can feel the lump once in a while but not that severe enough for me to take the car back.

Vesicant
05-30-04, 04:05 PM
Im speculating that if its a lump, maybe one of the cam shaft lobes have been flattened a lil bit.

VVT Could be the culprit too.. there are many things involved with that system.


What oil do you use? It only happens during idle and not when your driving? What about at a stop light... Does it go away when you "throttle" the engine to drive?

Devil_concours
05-30-04, 04:35 PM
Im speculating that if its a lump, maybe one of the cam shaft lobes have been flattened a lil bit.

VVT Could be the culprit too.. there are many things involved with that system.


What oil do you use? It only happens during idle and not when your driving? What about at a stop light... Does it go away when you "throttle" the engine to drive?
i notice it once in a while on stop light as well. Also it's more noticeable when you first start(more vibration). I'm making a list of all the things that are wrong with the car and taking it back.

http://www.cadillacforums.com/forums/showthread.php?t=13562