With engine running, out of cold loop, I turn on the lights idle drops to, say from 850RPMs to 600RPMs and doesnt recover unless you turn off the lights, and if you turn on the heater fan also at the same time, RPMs drop to 3-400 RPMs, just hardley running. I also driving about come to a stop, and the engine idles down to 600 RPMs. Ive replaced Idle air control valve, the old one was worn out, new fuel pump, and fuel regulator on top of the TBI, I thought about the MAP sensor, but I dont want to buy things that really arnt worn out or broken, if you get my drift? Any clues? Help!