1994 civic vx surges a few times at idle after i rev the engine but then it goes back to normal by itself, i took it to get smogged and it failed cause of the timing was off and to set idle, i cant happen to idle the car at 420 when the IACV is unplugged and with the throttle body idle screw turned all the way in, heres all ive done to try to fix the surge distributor and rotors, map and tps sensor, bled coolant, changed pcv valve, and tightend inatke manifold bolts cause they were kind of loose, new throttle body gasket, cleaned the iacv and tried diffrent ones, my engine is a d15b8 so it doesnt have a fast idle thermal valve, can someone give and info on what i can do or try because this is getting ridiculous, thanks for your time.