2004 21i running rough and smelling of fuel

[jester111e]

I have an 04 21i and I just summarized and it was run two weeks ago and then I took it out this past weekend and it seemed to
run out ok but it just smelled of fuel fairly strong and idled rough and just didn't sound all that great!
When I would throttle down from forward to go to reverse it made a kind of low clunking noise just before
the trasition of gears. my boat partner ran it nearly out of fuel the weekend before im thinking maybe trash in
the fuel or maybe injectors are dirty. any thoughts would be helpful. I have the mpi 5.7 efi with the g-force fuel system

[boatwakes]

Possible causes: out of tolerance coolant temp sensor, out of tolerance manifold air temp sensor, out of tolerance manifold air pressure sensor or, the most recent issue I've run across, fuel pressure regulator dumping fuel back into the intake manifold. In any case, you're going to need a MEFI code scanner and a fuel pressure gauge. The system should make fuel pressure when you turn the key to "on" and then NOT immediately lose pressure back to zero, if it does you may have a stuck injector or regulator problem but the issue will then be isolated to the fuel system and not a sensor. As for the computer, you need to be able to read and understand the codes, if any, that make an appearance in order to fix the problem. Start with fuel pressure and if it checks out, move on to the ECM diagnostics.