94 Del-Sol with a D16Z6.

Car when cold runs ok, idles high like it is supposed to and sometimes the idle drops down than jumps back up. However the problem is more ever present when it is warmed up. Idles around 900-1100RPMs, than stutters and almost stalls than jumps back up again to the high idle, Not up and down like IACV problem but more like it is running rich and stumbling. Sometimes it'll get bad enough and stall out. Pretty much stock, has a ghetto intake (Stock air box with snorkel removed), header, and exhaust. Nothing to crazy, checked all the vacuum lines, has new map sensor, new TPS, new IACV, has new o-rings on the fuel injectors, fuel injectors were cleaned and flow tested, has all new Bosch oxygen sensors, new spark plugs, new spark plug wires, and has in general been through a basic tune-up. Stock ECU.

Any ideas why it would be stuttering, stumbling and running rich?

I also have a video of it doing this. If anyone is interested in seeing it I can e-mail it to them. Just PM me with your e-mail and I will send it to you if you think it will help.

 

i have a 94 del sol and it seems to be doing the same thing.. at a stop light itll drop down to 100 RPMS.. then jump back up to 1 grand and idle there and stumble on its self again.. and repeat.. unno what causeing it..

 

Does it like once every thirty seconds to a minute?

 

mine seems to do it like every 5-10 seconds.. but itll steady out around 200-300 RPMS.. till i take off..

 

Up for the day crew.

 

Have you set the base idle?

Warm the car up completely.

Disconnect the IACV plug.

Using the idle speed screw (top left when looking at the Throttle body from passenger side). If it has never been changed there will be a wax plug covering the flat blade screw. Back it out, counter clockwise, RPM UP. Turn it in, clockwise, RPM DOWN.

It should be set to 500-650 RPM.

Plug back in the IACV.

Reset the ECU and bam it has a stable idle!