98 4.6 4x4 expedition. Codes The P0171 The truck idles fine, when under load it has an occasional miss. When accelerating is spudders and runs like crap. I've replaced plugs, coil packs, wires, fuel filter, fuel pump, idle control sensor, cleaned throttle body that was clogged, EGR, Injectors, 02s, cats, checked for vacum leaks on hoses and intake, cleaned MAF.
Misfire under load, poor acceleration
- Thread starter Randy T
- Start date
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Russell Lewis
Full Access Members
Did you check fuel pressure ?
Engine Running 28-45 psi
Key ON Engine OFF 35-45 psi
Engine Running 28-45 psi
Key ON Engine OFF 35-45 psi
Russell Lewis
Full Access Members
check fuel trim %
See if running lean or rich.
That will tell you how to hunt it down
See if running lean or rich.
That will tell you how to hunt it down
98eb5.4
Full Access Members
reminds me when i chased an evap code/issues & one of the first part(s) i changed out, to rule it out, came to roost,
ended up doing a ton of further stuff then i finally took it to folks who have the right gear & know how to properly diagnose & turned out the first part i changed with new, didn't work from the get go,
woulda saved alota time & money forking over the diagnosis cost first,
just to be clear, u still have the P0171 code?
did you actually check the fuel pressure?
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