I recently picked up a 91 rs 3.1l and it will start up and die fast, sometime will stay running up to 10 minutes but really rough. as soon as throttle is touched the car will die. i've checked the icm, fuel pump and relay, pressure checked it. checked the vaccums, also wondering if it could possibly be the air pump.

 

When it starts up what are the RPMs? Also does it smell rich. Your car could be dumping too much fuel into the engine and then causing it to flood and die. From hat youve told us thats really the only thing I can guess at the moment. More info would help.

 

I recently had similar problems with my 91 RS, as it turned out the #2 injector was grounding out and had to be replaced. It took alot of time and troubleshooting to figure this one out, but it would be worth checking out. We were able to figure it out by unplugging the injector(s) (we just guessed and started with #2) and see if the engine runs any different then with it plugged in. It should start missing on that cylinder as it runs, when plugged back in will smooth back out. But if it is grounded out (or shorting) it will not change the idle of the engine (and/or possibly make the engine die). What was happening is that as that injector would ground out, it would cut the power to the rest of the injectors, not allowing the car to run, but when unplugged it would run, missing on that cylinder. If possible I would take it to a local shop. If so, replace all the injectors at the same time, it will save you time and money in the long run. Good Luck with it!