Low MPG and mild fuel smell, possible causes?
Vehicle is a 1999 Ford Expedition XLT with the 5.4L V8. The CEL is not on and the scanner didn’t pick up stored codes.
Fuel smell is NOT in the vehicle and even running the A/C doesn’t make the interior smell of fuel. Smell is definitely outside the vehicle, but isn’t strong enough to easily pin a location down.
I know the plugs are coming due which might account or contribute to the mild fuel smell if they aren’t firing correctly. I’ve considered the O2 sensors but that should trigger the CEL. The other two things I’ve considered are the injectors/o-rings and the fuel pressure regulator.
Any other possibilities? Fuel filter, evap etc…
Comments
How’s the temp? I’d think you have a leaking injector or something’s messed up in one of the cylinders, like during combustion.
Temp is normal, never goes over half.
If there was a bad injector or plugs starting to fail it throw a rich air fuel mixture from the o2 sensor. So your correct that throw a code.
I think your on the right track with a bad injector o ring. Smelling around the fuel rail will conferm this. Most cars with OBD2 will have a fuel tank pressure sensor. Witch means it detect a leak. But your car is like right on the line of where it might not have that sensor. so u could pressurize the tank (cant stress this enough but low low pressure like 5 psi otherwise u can go boom) if u lose pressure u know its in the tank or evap emission system. Dont forget to check the fuel cap gasket. If its worn out replace it could be leaking.
There is also a charcoal container that collects and absorbs the vapors. This can get soaked and smell and no longer absorb vapers making it smell more. So u can open that up and lay the charcoal on concrete and light it on fire. This will dry it back out.
I had a fuel line leaking causing a gas smell and lower mpg. Try running it a bit and then look all the way along back to where the lines come out of the tank.