Rough idle at start up - 07RL
 

Very rough idle when first started, does not occur after initial start up. After the car warms up idle seems normal. Been to the dealer twice looking for cause of vibration in steering wheel when stopped at light with brake on and car in drive. Could this rough idle at start have any cause to steering wheel vibration? Motor mounts all good - throttle body good - computer diagnostic shows nothing. 07 RL 27,000 miles.

Are your RPMs fluctuating, or are they so low it feels like the car is about to die?

spy - no on both questions - tach remains steady no fluctuations - only during first start up of the day - last week drove to dealer by the time I got there vibrations in steering wheel when brake applied in gear stopped. The computer showed nothing - planning on leaving car over night with dealer and let them cold start it next day - rough idle - vibrations in steering wheel....

What are your RPMs on first start up?

spy - first start up 1100 rpm....30 seconds down to 1000 rpm.....another 30 seconds down to 900 rpms...and steady with no fluctuations for several minutes and does not sound like it's going to die....vibrations in steering wheel while in Park?

I had a similar problem in a different car. I went nuts trying to figure it out. Rough idle at start, then smooth. Dealer thought it was a bad o2 sensor, vacuum leak, and anything and everything else.

Well, after days at the dealer it turned it to be one small, god-foresaken spark plug that had degraded and wasn't gapped properly.

I'm not saying saying that this is applicable in your case, but sometimes the dealer or mechanic will overlook the most obvious and simple solutions and zero in one something else, like what happened to me.

Good luck!

My 06 RL has a slightly "lumpy" feeling idle for a few minutes on the first start of the day, which I believe is related to how the ECU tries to keep the mixture lean before things get a chance to warm up to keep emissions down. My buddy's 06 TL does the same thing.

Legend number one had some major idling issues at the end of my time with it. I never even thought about spark plugs, and I was at 190k. 27k seems low, but not impossible.