My 57 Chevy with a 89' 350 TBI is having an idle issue. I believe I tracted it down to the IAC but need to confirm as it is a new IAC valve. The car doesn't increase idle at startup or the normal idle increases. It actually will not start unless I crack the throttle. I'm getting 52 ohms through A to B and C to D on the IAC. The wiring diagram for the specific motor showed the wiring different that the connector. I switched wires with no luck. I get 10.5 volts on both sides of the 4 pin connector. How do I tell which side is high side and which is low side? The IAC does go back and forth when I switch wires around. I've been goofig with this for a year and I need to fix this. I can push the pintle in and the car fires right up reaching through the window. After a few starts the pintle close and it's back to hard starts and low idle. I need to esting information and how to determine which wire goes to which pin on the IAC. I have the wiring diagram if needed.