2002 Ranger 2.3l Idle problem
When at a stop light the engine idles with an uh-uh-uh-uh, sort of a pulsating idle between 900 & 1200 rpm. Not that it pulsates between those 2 numbers, but that's the range it idles in. When it's in park it sounds fine. Pulled codes: 1451. Looked under the bed and found the sensor unplugged, so I plugged it back in. The code didn't clear.
Also I checked vacuum lines, found one and replaced it. Also the IAC tested bad resistance, I replaced it. I noticed too, that the temp gauge measures constantly cold. I realize these problems feed into the computer. Would these idle symptoms be caused by incorrect readings on the temp gauge? I replaced plugs, plug wires. I took it to a mechanic and he found the PVC vacuum line was leaking and he replaced that. Any ideas?
Also, I posted this on another forum. Just trying to get coverage:)