I recently purchased a 95 mazda 626 with a 2.0 automatic transmission. It has terrible problems idling it idles too low 500 rpms, too high 2000 rpm's. My mechanic replaced a heat sensor on the engine. It is a little better, but idle rpms are still all over the planet.
He belives it is the idle air control valve?????
Please help with any recommendation.
Thanks
vffdoug

 

Sounds probable. I would check for vacuum leaks first. Also clean the MAF hotwire and check the thermostat. If it sticks open it can think its a cold engine and bump up your idle. I'm sure he has already cleaned the throttlebody out.