PLEASE HELP!!1992 NSX auto, my car starts, but high idling about 2500rpm

[summersky1984]

hi, I need your help, can't seem to figure out the problem, whether its the air intake temperature sensor, vacuum leaks, or the egr valve. My car starts, at about 2500 rpm, then a few minutes later, it goes down to 1500rpm and up to 1700 rpm, then down again a little, etc. Once I drive it off for 5 minutes or so, the car is back to normal idling, at neutral or parking at .900 rpm, can anyone help me solve this... thanks

 

[Honcho]

It sounds like your fast idle valve is bad. You can replace it from Acura for about $100.

 

[summersky1984]

hi HONCHO, thanks for replying, should I clean the fast idle valve because they discontinue these parts for the AUTO transmission, should I be looking into the idle air control valve as well? is cleaning would help or replacing them? thanks for you help..

 

[Honcho]

If the idle is hunting like that it means the white plastic insert inside the valve has come loose and is causing an intermittent vacuum leak. You can attempt to fix it by removing the top of the valve (make sure to buy replacement o-ring p/n 16075-PE2-005) and screwing the insert back down. Do not screw it too far or you will lose the fast-idle function altogether and the car will stall on cold starts. You might want to check Rockauto to see if they have the part.

Your car is over 20 years old so both the FITV and EACV could definitely use a cleaning, but that is not the likely cause of your problem. I am about to do a full cleaning and overhaul on my intake manifold/TB and I will post up everything with pics.