25th92RS

iTrader: (4)

After a long winter I go to start my 92 RS w/ 305 TBI and it idles great at cold temps. It warms up and the idle RPMs drop to normal levels. Then every once in a while I'll get a little surge. Revs up nicely, but will bog way down when trying to level out again. The Injectors will pulse a few times during the surges. When put into gear it will stall out every time unless given throttle to keep it going. Any type of load on the engine seems to kill it or bog it down if it's at 1000 rpm or less. Ex: starting the cooling fans, ac pump, any gear, etc... I replaced the O2 sensor, eliminated the EGR, adjusted idle speed, checked for vacuum leaks and actually fixed a major one. I gave it a good tune up this winter and it runs like crap after a tune up. No codes are being stored or shown either. I have a Hypertech PROM in the ECM. I'm really lost on this one. My next venture is on to the fuel filter. After that I don't know what to do. Any suggestions will be greatly appreciated. Thanks!

topless89

check the fuel pump relay. mine had some pretty bad wires going to it and there was actually a burnt spot where one of the wires plugged in.

rocko350

The symptoms you describe makes it sound like its time for a coolant temp sensor, and a good cleaning of the ecm grounds on the thermostat housing stud. Have you monitored the fuel pressure during the stall condition? Unhook the battery first after you warm up the engine. this clears the fuel tables and reverts back to base maps then "relearns" fueling. Sometimes after a tune up the engine runs worse this is the first thing i try.

25th92RS

iTrader: (4)

Turns out it is nothing that we have suspected so far. Not the O2 sensor, Intake Air Temperature Sensor, Fuel Filter, Fuel Pressure, EGR Valve. We did fix the timing. It was advanced a little too much, but still didn't fix the problem. I'm looking into the Idle Air Control Valve next. After all of this troubleshooting and wasted dollars I find a description of a faulty IAC Valve that directly relates to my problem. Go figure. Please keep the suggestions coming!