1993 z28 122,000 miles,sometimes it just doesnt want to start like its flooding. you can keep trying to crank it and give it some gas and it will eventually. if you stop trying to crank it, it will buck and act like its trying to, and you can hear the intake sucking in air.

Also this *normally* only happens on the first crank of the day or when its really cold outside. when the car does start though black smoke comes out the back. BUT it will drive fine after I get started, and you can turn it off and crank it right up without a problem.

 

Sounds like a fuel-pump problem. Try giving it a shot of carb cleaner down the intake before you crank it over tomorrow morning. If it starts up easy and runs like normal, you are looking at a fuel pump on borrowed time. Fuel pres. seems to be most critical at cold start-up. I'd suggest checking the pressure with a guage before you throw a fuel pump at it, but thats just what I'd do!!! Good luck.

 

Possibly the engine coolant temperature sensor may be the culprit.

 

fuel pressure at idle was 47 so we dont think its the pump,theres a bad smell of gas coming from the engine when im trying to ge it to start so the mechanic thinks theres a leaky or sticky injector,I got it to start so I ran some injector cleaner with a full tank and added 2 gallons of 100 octane gas so hopefully that should clean the system out,if I still have the problem come monday my mechanic is checking the injectors

 

Leaking injector is a possibility. That doesnt happen alot on GM's, but if its flooding after sitting for awhile, its possible. Have the mechanic look at the fuel integrator and block learn #s with a scan tool. If they show that the ECM is taking fuel away, I would be very suspicious of a leak. Keep us posted.

 

Check the fuel pressure with the key on, not start (fuel pump will prime and then shut off). Verify your fuel pressure doesn't drop off quickly after the prime ends. If it drops quickly, it's likely that your check valve (located in the fuel pump) is faulty. The check valve ensures proper fuel rail pressure for starting. A leaky injector will also cause the pressure to bleed off.