Okay 95 civic d16z6. Car runs fine when cold but starts to fluctuate once at operating temperature. I've replaced the iacv, fitv, tps, map, coolant temp sensor, and still the fluctuating continues when engine is warmed up. Also my rpms will stay at 2k when coming to a stop and shifting to neutrual. But this only happens every once in a while. Any suggestions on what could help would be appreciated. These 2 problems are really starting to bug me

 

Get rid of the fast idle thermal valve. But simple test remove you intake tube start the car and plug one of the two hole is the throttle body with your finger. Upper one leads to MAP lower leads to fitv.

 

What do you mean get rid of it? The car used to fluctuate like crazy when I first got it. Once I replaced the fitv it stopped. Now it only does it when warmed up. I plugged the hole and still has small suction when the car is warmed.

 

You can block it off or get an aftermarket throttle body that doesn't have one. All it does is you something like a thermostat to create a vacuum leak to idle the car higher on cold starts. You can take it apart and make sure its still in one piece also