I have a '95 GT. Like most other stangs purchased as used, some bone head tore into it. It has shorty headers, NO CATS, and flowmaster 50's. It has a rough idle on start up, and actually has to warm up like a carburated vehicle of old, and rarely does the engine temp get above 140-150 degrees. EVER! So, I replaced the CTS. Nope, not the problem. Replaced the thermostat and gasket. Nope, not the problem. It constantly runs rich and cool. I could use any helpful input. I don't have thousands of dollars to throw at it, but if ANYBODY has a suggestion, please let me know.



Thanks


GH71

 

It can be rough troubleshooting with unknown mods. So you have to start with the basics. For troubleshooting on a budget a parts store with a good selection of rental tools that they will let you use in the parking lot is the best. So find a parts store that has thier act together.


Take a look inside your MAF at the wires if they are fuzzy then they need to be cleaned. A MAF wont cause an engine to run cool but it can cause a rough idle on cold start.

Drive into the parts store and start with a lazer thermometer on your thermostat housing to make sure the engine is actually running cool. This will eliminate a gauge problem.

Next pull the codes and see what you have.

Next put a pressure gauge on and see if your pressure is running high because of a bad regulator. A bad regulator will cause a rich running engine and rich engines run cooler. But you are at an extreme for cool engine.

These are some cheap and easy tests to do on a budget with a good parts store available.

 

Always check codes first
If I was a betting person I put money on your o2's most headers will kill o2's within a month of driving once they go through a few good heat cycles I always end changing them out