Mechanics

ROUGH IDLE

1997 Ford Expedition

Engine Performance problem
1997 Ford Expedition V8 Four Wheel Drive Automatic 182000 miles

when I start my vehicle it is rough idling, it stutters when you accelerate but as soon as you get to abou 15mph it starts to smooth out and runs better, I have changed the coil packs, plugs, wires, fuel pump, fuel filter, and there is a mis fire on #3. Can you help?
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Pmedic666
November 16, 2008.




*If it applies -check compression and * injector for that cylinder

Misfires can be caused by worn or fouled spark plugs, a weak spark (weak coil, bad spark plug wire), loss of compression, vacuum leaks, anything that causes an unusually lean fuel mixture (lean misfire), an EGR valve that is stuck open, dirty fuel injectors, low fuel pressure, or even bad fuel

Might also want to check the idle air control valve/motor and throttle position sensor-

Tiny
Rasmataz
Nov 17, 2008.


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