Hey guys. My idle shows about 1400RPM on the tach, but my scan tool shows it as about 1200RPM. I hooked a vacuum guage up to the manifold and got 18 inches of vacuum. Is this a normal reading for a stock (i think) lt1?

I took the IAC out and checked the amount of ohms between terminals A and B, then C and D. Im getting around 50 ohms for the first terminals, but Im getting OL for the second.. So I need a new IAC?

I was searching for a new IAC on the common parts places, but they are all quoting me around 130-140 bucks! I looked at the IAC from my mom's car (2005 Imapala w/ 3.8L) and they look identical. I looked up her cars IAC on the same site and the pics are the same. But the they only want $30 for the one for her car and they actually have it in stock.. they wanted to order mine. Is there really a difference, or are they charging more for the same part? Heres an example:

http://shop.advanceautoparts.com/web..._536973024___#

http://shop.advanceautoparts.com/web..._536978813___#