I have a 90 NA that does not idle well when warm. The car will idle and then drop off until almost dying and then just hunting back and forth. The car idled perfect when bought with a bad motor. After rebuild, I couldnt get the idle back to perfect. I have had the upper intake off twice thinking vacuum leak to no avail. Switched the TPS tonight and nothing. New air filter, new fuel filter.

Any ideas?

Brian

 

After changing the TPS did you set it properly?


Santiago

 

I had a fluctuating idle issue myself when my car was stopped and the clutch was engaged. I called a rotary specialist and he suggested the clutch switch might be bad. Turns out I had a broken spring in my clutch switch which is located behind the clutch pedal. All you have to do is unscrew the clutch switch from the pedal and open the switch using a flat screwdriver. Inspect the switch, clean it with alcohol and make sure the spring is in one piece. If not replace the spring and you should be fine. Or you can just purchase a new clutch switch- shouldn't be that expensive.
Also make sure your idle is @ 850 rpm in neutral after the car is warmed up (drive for 10 minutes). adjust idle screw at top of manifold with black rubber cap. Clockwise to idle down... and counter-clockwise to idle up.

My idle is PERFECT now!