1998 Ford F150 p0305 #5 misfire

1998 FORD F-150
102,000 MILES • V8 • 4WD • AUTOMATIC
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CHAULKMONSTER
  • MEMBER
  • 2 POSTS
COMPUTER GIVES ME A P0305(#5 MISFIRE). IVE REPLACED BOTH COIL PACKS, WIRES & PLUGS. ITS NOT A CONSTANT MISS. IT RUNS FINE FOR A COUPLE OF MILES & ALL OF AT ONCE IT STARTS MISFIRING & THE CHECK ENGINE COMES ON. THE INJECTOR ON #5 SEEMS TO BE CLICKING LIKE THE OTHERS. COULD IT BE THE FUEL PRESSURE REGULATOR, CRANKSHAFT LOCATION SENSOR, OR CLOGGED INJECTOR? ANY SUGGESTIONS WOULD BE GREAT. THANKS
Feb 24, 2009 at 10:46 AM
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RASMATAZ
  • ✓Experienced Mechanic
  • 75,992 POSTS
Sparkplug was replaced now check the compression and injector for no.5

Misfiring 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.
Feb 24, 2009 at 11:05 AM
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