So my 2001 S with 32K and a Vortex Supercharger on it had an idle problem end of last year I just got to. It was not holding any idle and would stall when I stopped and it would also stall out while driving at speed if I let off on the accelerator completely. So.. I replaced the IACV Idle Control Valve. After that I drove and warmed up the car and the idle would stay at about 2800. Next I returned home, disconnected the battery each time to clear the ECU and performed the Idle Relearning Program twice. Both times the idle would be good when I first started the car but soon as I rev the accelerator while standing still the engine begins to fluctuate the idle back and forth between 1200- 1800 RPM constantly. I have not tried driving the car since then. Any ideas or suggestions?

 

A vac leak ?

 

I guess that's the next SIMPLE thing I will check out . (But simple usually doesn't work out for me!!)

 

Thinking about it more, although I will check for the obvious, ..I'm not sure how it would be maintaining the correct idle till I pumped the accelerator though if there was just a vac leak. ????

 

HFC or oem cat ? could be an exhaust sensor related,or media in cat broken up.

 

Wow … not sure how I would be able to diagnosis that one!!