i posted this over in the TL forum since i have a 05 TL, but no one seems to know anything.

Only happens when the car is started after sitting over night. basically the idle searches from 750rpms-1200rpms until the car is warmed up.

The dealer has it right now, and can't figure it out. they are running worthless tests like compression tests. i've read the entire service manual, and of course there is no idle air control valve like older honda/acuras which would case this to happen

 

Unless it's completely going wacko, I say don't worry about it.

 

Its normal for our TSXs to rev a bit higher upon startup until the engine warms a little, then the revs drop. However, the hunting you describe is unusual, not what it should be doing. I don't know if the RPMs at startup are controlled by engine temperature or just a timer but I suspect you either have a bad sensor or a bad ECU. I'm not an expert on this so please don't take my guess for fact. Maybe someone more knowledgeable than me can chime in.

 

Have the dealer read the 02 sensor reading at idle through the ODBII port. Is it staying at a constant 14.7? Do you have any CELs? Any major loss in fuel economy lately?

 

the dealer doesn't want my input. which was what i tried to do yesterday, and to answer your questions, no CEL's fuel economy is normal. the only issue is at a cold start idle, otherwise the car is perfect

 

could be the ecu learning? i've seen this happen on FD's and M3's quite a bit...

 

as long as the car didn't misfire it will be fine, for me, when it was idling around 1000 - 1500 rpm, the whole car kinda vibrate a bit, i felt it seating there.......i even open my hood and check if there's any "bad thing" going on in y engin but no........so i assume it's normal

 

It sounds like some type of valve that is temperature controlled or monitored that connects to the intake manifold. How about item #8 in the pic below? It's an actuator assy, bypass valve. See if you can remove the valve and look for a clogged screen that might be blocking the correct air flow.

 

that was the first thing the dealership tried. it didn't work

 

i was thinking that too, but that valve isn't supposed to open until a certain RPM, i think it's around 2500. otherwise it's supposed to stay closed

 

just got off the phone with Acura as i was typing this out, seems as if one of the O2 sensors died, but wasn't causing a CEL

4 months ago i took the car in for service because of a CEL which was for the rear primary O2 sensor, but by the time i got to the dealer the CEL cleared, and they told me nothing was there. Guess they should have listened the first time i went there