2002 Acura RSX base, K20A3, 114K miles. I recently removed my throttle body to clean it. Pulled the MAP and purge control solenoid and IACV. Cleaned the TB and IACV (after removing the electronic control) with Valvoline TB cleaner. Used new gaskets and O-rings all around. Performed the idle relearn procedure.

The problem I was experiencing with the idle dipping too low is gone, but now it seems to hang a little high. Maybe this is normal. Cold idle starts at ~ 2K, which seems high, but the temperatures here are now beginning to get wintry. Today's high was around 45.

When I was cleaning the TB, I noticed what appeared to be scoring from the throttle plate, as evidenced by an elliptical discoloration surrounding the apparent path of the throttle plate on the intake side of the TB bore. Unfortunately I was in too much of a hurry to take photographs.

Is this normal? I ran my finger along the discoloration and couldn't perceive any gouging. Also, I was unable to move the throttle plate in any direction other than along its axis by hand.

I'm wondering if there is damage to the throttle body that I can't feel with my fingers but that might be causing excess intake air to enter the intake manifold and thus causing erratic and intermittent idle issues.

Also, I've read differing accounts of whether IACV's are cleanable or not. I've read that cleaning an IACV will only provide short-term benefit, and that it is a non-serviceable unit. Unfortunately, on this car it is a $200 unit. And it is prone to clogging quickly, situated as it is on the bottom of the TB. I replaced it one year ago this month.

I doubt that the scoring is very much of a problem. I've always cleaned my IACV with brake cleaner and it has worked great. You may need to readjust the throttle cable a little bit; i.e. back off the rear throttle nut.

Check the Fast Idle Thermo Valve. Remove cover (two hex head screws) and ensure plastic ring, which goes around the valve, is rotated clockwise until it's fully seated--don't overtighten. If it's not seated, it allows in too much air, which the ECM keeps trying to adjust for. On my Civic, it's located under the IACV on the back of the plenum. It's hard to see, but it's there.

Thanks! Oh, yes, I'd forgotten all about that little bugger (the fast idle thermo valve). So many things to consider on these computer-controlled cars.

Just looked at it - I don't see any cover, and the only thing that can be tightened is the fitting that secures it to the water outlet. That wouldn't control airflow, only coolant. There are two hoses - maybe they are worn? They look OK though.