I have a 97 z28. When I bought it (3 years ago) it had a bad temp sensor making it think the car was -40 degrees and dumping tons of fuel. When it did this, it had a hard start once warm, threw a code, ran like crap, etc. but ran better when unplugged. Anyway, changed it and all has been fine for 3ish years. Now my plugs are fuel fouling within 10-15 minutes. No codes, no hard start, idles and revs perfect. Hooked up a live data scanner and it says coolant and air intake temp are -40 degrees. Found the wires at the pigtail for the temp sensor to be messed up and little bit, fixed them, and still reads -40. Replaced the sensor itself and still reads -40. Traced the wires all the way back as far as I could and they looked perfect. Am I missing something? I'm stumped. Pretty sure nothing else causes these cars to believe the coolant is -40..

 

Most likely a break in the wire between the PCM and sensor. You're gonna have to ohm them out.

 

Yeah, I just looked at shbox's website on what they are supposed to be. On my way back to our shop to check now