Hey guys was having some awful idle problems not long ago. I change my idle air control valve and my idle got better but not perfect. If I give the car gas when the car is in neutral once the rmps start dropping it'll stay at 1 1/2 for like 2 secs and it'll go back to normal or it'll drop to normal go back up and come back to normal and it'll idle fine after that. It's a 93 hatch with a b18c Japanese type r. I replace the iac valve and pcv valve and all my hoses are hooked up and in good conditions. Any ideas on why it does that?

 

Bump

 

^

 

Maybe a small vac leak. Unplug your iacv and see if it still does it.

 

check your spark plugs,clean the throttle body really good, maybe some loose screws or bolts, bleed your coolant...loose hoses maybe.

 

could be as simple as a bad oxygen sensor...they don't always throw codes...especially on obd1 cars

always go Densor on oxygen sensors