Pontiac Repair: hard start, temp black smoke, runs good, no restart for hours

Question
95 Pontiac grand prix v6 3100. Hard start, when it does blows blue black smoke for a min, then it runs great wherever we are going. We turn off the engine and it wont restart for hours.tried cleaning air box and mad but it didn't have a normal maf(cylinder with sensor bars)just a small sensor in the air canal between the filter and intake.(cleaned it no help).???

Answer
Hi Richard:

any ses light on when it's running? if so stop by a big box auto parts store and let them scan the car for codes it could lead to the issue. the fact that it billows black smoke means it running overly rich it could be for a few reasons one of the engine sensors is skewed and throwing the misture off. with out a scanb tool your will not have the ability to see what's going on so it's not a do it your self job. the other thing it could be is a leaking injector(S) when you shut the car off the pressurized fuel leaking into the engine and 2 things happen the fuel in the lines boils and hydro locks and also the fuel vaporizes in the engine and it's over ly rich and will not run. that can be check with a fuel pressure gauge. put a guage on the fuel rail pressure tap run the car ans hut it off and watch the gauge the pressure should not drop very much with in say 15 minyes if it slowly drops off ther injectors are leaking  the fuel pressure regulator is leaking oe maybe even the check valve in the fuel pump is bad allowing the fuel to drain back into the tank again this is not really a do it your self check repair either.. fuel injected cars are not a DYI job.
good luck.