Ok, I fixed the problem with my car getting enough fuel, turns out I had one bad injector on my TBI set up, but now my 91' RS will only run perfect when the motor is cold, When its cold it starts fine and runs like a champ, but once it warms up it just hits the fan. It starts to spit sputter and pop like its about to dye every time I give it gas, A mechanic friend of mine told me it is 9/10 the temp sensor for the motors computer. I need your guy's opinion on this diagnosis before I go screwing around with the ECU. The symptoms are, when it warms up it will shutter and I will hear a loud popping sound coming from under the hood like its about to stall out and dye, it will come out of it about a mile down the road, and run poorly still then, could this really be just that sensor?

 

Unplug the temperature sensor (the probe in the air cleaner base) and see if that makes the engine act any differently when hot.

 

i just had an issue with my truck that was very similar to what you are seeing. the temp sensor (ect)was seeing -40 degrees. changed sensor and it runs great. it was running way rich,

 

Can you tell if the engine is running rich; black sooty tailpipe, or do your eyes burn when behind the car with the engine idling?
Your open loop/closed loop issue could be the air temp sensor, a bad connection to it, bad 02 sensor, bad engine temperature sensor (not the other one for the gauge). Or if the fuel pressure regulator is bad it will be dumping too much fuel in the engine. Pull the vacuum hose off the f.p. regulator and check for gas. If there's any in the hose, replace the regulator.
Have you flashed for error codes? You could have some present, even if the check engine light isn't on.