My sons car ,91 CHEVY CAMARO RS 6 CLD ,broke down and would start for 5 secs or so and stall like you turned the key off.So I STARTED off with what thought was the cheapest thing CAP and ROTOR.Car ran for about 2 blocks then stall and would run for 5 secs and shut down.The following is everything in order of replacement.
CAP ,ROTOR,DISTRIBUTOR(his was a mess ,cracked wire casings and plug to the control module was dry rotted and broke,rusted to hell)SPARK PLUGS,WIRES.After this we checked to make sure we were getting spark and we are getting it w no problem.Changed the ECM (computer)Car fired right up and took it for about 10 mile test and ran GREAT.Got home shut it down and tried resartng it and did the exact same thing ,ran for 5 secs and stalled.Installed a TPS(trottle position sensor)car STARTED RIGHT UP AND RAN GREAT for 5 10 mins then we shut it down and tried to restart it and did the exact same problem.Friend came over and sprayed carb cleaner in trottle body and car would stay running till he stopped spraying.So now we start checking fuel pressure and it was between 40-47 psi like the haynes manuel said.Didnt lose presure at all.So I figured were losing fuel/pressure from the fuel rail to the injectors,so i replaced the FUEL PRESSURE REGULATOR and checked the FUEL INJECTORS with a noid tester.All are fine.Replaced the MAP SENSOR and didnt fix prblem.Checked the computer for troubleshooting codes,doesnt have any.SO im at a total HEAD SCRATCHER here and any help would BE GREAT.BTW its a 91 CHEVY CAMARO RS 6cld.engine

 

im not sure what you mean by a 6cld engine, but it sounds like you are having a very hard time. try replacing the fuel pump relay, and the oil pressure switch. im not exactly sure where the relay is, but the pressure switch is typicly located near the oil pressure sending unit. if i knew what engine you were talking about, i could advise you to where it is. the ecm will run the fuel pump for 5 second after cranking, and then looks to the oil pressure switch to keep the fuel pump on. if it is below 5 psi, the switch wont close and the fuel pump wont stay on. check the connection and wiring to it as well

 

I wouldn't bother messing with the fuel pump relay. The relay primes the pump when the key is first turned on, then switches off, and is bypassed once the engine is running. As long as the engine is starting, the relay would be working, and you should hear the pump prime. Since the engine is running for five seconds, it sounds like you're burning off the prime, and the pump isn't being told to keep running.

 

Sorry it is a 3.1 L V6

 

We have already tried the relay. our ECM is running diagnostics and we tried getting a code, and its not giving any codes

 

Are you getting oil pressure? If the sending unit for oil pressure is bad it will shut down fuel pump