1997 Mustang Cobra (4V, 4.6L), rough idling, won't stay running
The car hasn't been driven in over 2 years. I flushed the gas tank, changed the fuel pressure regulator, changed the oil & filter, installed a new fuel filter, EGR Valve & PVC valve.
When I disconnect the MAF electrical connector, the car idles and revs fine but dies as soon as I reconnect the MAF. Although, after idling for a few minutes with the MAF unplugged, the problem does reoccurs. I am not getting any trouble codes reported. I've back probed/tested the EGR vacuum regulator and pressure differential meter, within spec. I've replaced the MAF with an after market one, same problem persists. I'm at a loss for ideas.
When the car idles/runs rough, a heavy gas smell persists with black smoke coming from exhaust. Obviously the engine is running overly rich, but why. When I had the EGR valve removed. the engine idled at a very high RPM. When I partially blocked the EGR valve opening in the intake the idle reduced to normal. My thought was that the TPS was bad, but my code scanner/diagnostic scanner displayed reasonable TPS values compared to another ford I have.
P/S. The car ran fine before the 2 year hiatus.
When I disconnect the MAF electrical connector, the car idles and revs fine but dies as soon as I reconnect the MAF. Although, after idling for a few minutes with the MAF unplugged, the problem does reoccurs. I am not getting any trouble codes reported. I've back probed/tested the EGR vacuum regulator and pressure differential meter, within spec. I've replaced the MAF with an after market one, same problem persists. I'm at a loss for ideas.
When the car idles/runs rough, a heavy gas smell persists with black smoke coming from exhaust. Obviously the engine is running overly rich, but why. When I had the EGR valve removed. the engine idled at a very high RPM. When I partially blocked the EGR valve opening in the intake the idle reduced to normal. My thought was that the TPS was bad, but my code scanner/diagnostic scanner displayed reasonable TPS values compared to another ford I have.
P/S. The car ran fine before the 2 year hiatus.
Cars & Trucks - Ford - Mustang - 1997 Ford Mustang Cobra
Answers & Comments
Silly question, however did you check the air box for nests. it is not uncommon for rodents to climb in and make themselves at home. i would also say to get a maf from ford. check ALL around the engine compartment and underneath for evidence of rodents and their leavings. youll be very suprised what you may find.cheers
replace the MAF if youre convinced there are no broken wires or bum connections to the MAF.
It seems you have a problem with firing into combustion chamber,did you check if there is spark coming to all cylinders? It may also the coil pack that sits on the spark plug or the wiring to it ,whichever applicable.Be careful as this could cost a lot in terms of buying parts..hope this helps.
Bad fuel pump module assembly.
Bad fuel pump module assembly. Fuel Line Pressure Test proved fuel pressure was too low. After replacing the fuel pump module assembly, the car ran like a champ.