I've had my Acura TL layed up for a couple of months and now that we are driving it again the engine is reving, you really notice it in N and P, it just revs up,down,up,down. You can also feel it when your driving, it speeds up on its own. We had it layed up over the winter and it did the same thing in the spring, but after one good run never did it again until now. I've had it into a shop and they put something in it to try and clean out the engine (thats what I got out of it anyway) but are saying its still doing it now. I'm thinking maybe its a sensor? When in park after its been reving for a bit some lights will come on (TCS etc.) Any help I would appriciate, i'm hours away from a Honda dealership and the shops around here are stumped!

 

Have you made sure the coolant is topped off?

Might also want to check the IACV, from what I'v read it is under the throttle body on a 3.2 TL should have 2 coolant lines attached to it, may want to try and clean that out, and see if that helps.

 

If this is drive by wire like 2004+ TL then I would look at that sensor as well. They fail quite frequently. I just had my wife's replaced. Car did that plus one day it just came out of first gear into traffic and then died and she floored it to get it off the highway. It went about 5mph floored. Check into it.