Been dealing with an inconsistent idle since we acquired the vehicle. It has gotten worse and now stalls at stops. The idle varies between 500-1200. Seems to smooth out a little once it warms up, but it's still bad enough to stall frequently.

Can't find any vacuum leaks or air leaking around intake manifold. TPS tests OK w/ a multimeter. Chilton says to read the four pins on the IAC valve. Should get 20-80 ohm on "one set" of pins and infinite on all others...

We get 50 ohms on one pair of pins, 50 on the other pair. And infinite resistance on any other combination of pins. Does anyone know if that sounds OK. I'm confused as to what Chilton's means by "one set" ???

Any other ideas? This idle problem used to be just a nuisance, now it's becoming a major pain in the ...

Thanks in advance!