98 mustang gt 4.6l rough idle even worse when it gets warmed up

Salsage

New Member
May 16, 2022
3
0
1
43
40419
I have a 98 mustang gt 4.6l everything stock. When u start it up it has a miss . Strong gas smell .if u hold it a certain rpm it cuts out misses even worse. When it warms up it's even worse. The parts that is replace are injectors,coils,fpr,plugs, wires,mas, tps was checked good. All o2 sensors, temp gauge and temperature gauge to computer. Vacuum lines. And fuel filter. And it will not show a check engine light either. I'm stumped.
 

DaBard

Member
Jun 17, 2020
14
1
13
71
Rochester NY
"Strong gas smell" indicates you may have a crack in the fuel line. That "it gets worse once warm" seems to indicate that the fuel pump isn't delivering enough fuel per demand, which may be the pump itself, or a problem between pump and engine in the fuel line, or the fuel is getting heated excessively before it gets delivered to the injectors (a lower probability condition, but something to think about).

If you live (or the vehicle has lived) in states that use a lot of salt in the winter, fuel line corrosion/failure becomes more of an option (also applies to brake lines).

Let us know what you find...
 

Mach1.0

New Member
May 29, 2022
15
0
1
49
Texas
I have a 98 mustang gt 4.6l everything stock. When u start it up it has a miss . Strong gas smell .if u hold it a certain rpm it cuts out misses even worse. When it warms up it's even worse. The parts that is replace are injectors,coils,fpr,plugs, wires,mas, tps was checked good. All o2 sensors, temp gauge and temperature gauge to computer. Vacuum lines. And fuel filter. And it will not show a check engine light either. I'm stumped.
Hey, do you have a battery charger? Would be interested to know if after an overnight charge the symptoms improve for a little while then return.
 

Mach1.0

New Member
May 29, 2022
15
0
1
49
Texas
Hey, do you have a battery charger? Would be interested to know if after an overnight charge the symptoms improve for a little while then return.
Is the gas smell coming from the exhaust or elsewhere? If it's coming from the exhaust, a misfire could account for the smell since unburnt fuel passes out the cylinder, and if enough of it, through the cat. There should be a trouble code if it's that's bad. You can pull the harness to each fuel injector until you don't notice a change in idle. That would identify the cylinder that's misfiring.
Let us know about the battery charger question because there's more info on that train of thought.
 

Salsage

New Member
May 16, 2022
3
0
1
43
40419
Is the gas smell coming from the exhaust or elsewhere? If it's coming from the exhaust, a misfire could account for the smell since unburnt fuel passes out the cylinder, and if enough of it, through the cat. There should be a trouble code if it's that's bad. You can pull the harness to each fuel injector until you don't notice a change in idle. That would identify the cylinder that's misfiring.
Let us know about the battery charger question because there's more info on that train of thought.