Since the transmission of my Acura TL was replaced by a nationwide transmission specialist, I have been having problems. Unfortunately, the specialist claims not to be able to reproduce the problem and is not willing to take the transmission apart to fix it without knowing what the cause could be. I am looking for suggestions.
The problem appears in two different forms, which I think are related in some way:
When the engine is cold and I have driven a very short distance (often less than 100 yards), the transmission sometimes does not shift out of idle. E.g. I brake for a speed bump and when I give gas again, the engine revs in idle. This happens intermittently and only once per trip.
When the engine is hot, e.g. after having driven for an hour and I am in stop-and-go traffic, the engine starts revving up, even when I have my foot on the brake and don’t give gas. Yesterday, I shifted the transmission to Park and the engine was still going at 2000 rpm. I started having this problem when the weather got hot, but that could be a coincidence.
What could cause this behavior?