justang97

replaced the fuel filter and cleaned the MAF and it was running awesome...then right when i pulled in the driveway it cut off and when i cranked it back up it started stuttering and shootin out black smoke..

justang97

there is also black stuff comming out the exhaust..not just smoke, my garage had black all over it from the exhaust..could it be my cats?

cliffyk

It could be that the fuel pressure regulator (FPR) is sporadically not doing it's job--not opening to control the return flow and causing the fuel pressure to jump to the 60+ psi the pump is capable of.

You can monitor the fuel pressure to see if this is happening, however it's kind of a hassle to hookup a test gauge.

A quick check (only a check) is to measure the vacuum at the FPR vacuum port--with the engine idling it should be 18 to 22 inHg; if not then the vacuum line may be blocked or collapsing.

With the hose disconnected and capped the fuel pressure will rise to it's maximum, which should cause a noticeable change in the idle--unless it's already idling like crap when you do the test.

If you have good vacuum (18-22") at the FPR, and the engine's running rich at idle, then the FPR is stuck closed--replace it...