1997 Ford F150 skipping after warmed up

1997 FORD F-150
320,000 MILES • V8 • 4WD • AUTOMATIC
Avatar
CSPRINGER826
  • MEMBER
  • 9 POSTS
i have a 97 f150 4wd with the 4.6 this has been a good truck but for the past year now it has a consitit skip at low idle like whe the over drive is on but when off runs smooth as can be i had done a tune up on it plugs plug wires coil packs air cleaner the whole nine yards now after i cjanged the plugs it runs smooth all the time for aboput 500 miles then starts to miss again and i have replaced the egr valve and i have scanned it and no codes come up no check engine light nothing it has me stumped the only thing i can think is a vacum leak and i have replaced the motor due to a bad oil pump wiping out all of the crankbearings
May 31, 2008 at 5:59 PM
Advertisement
Avatar
MASTERTECHTIM
  • CAR REPAIR CONTRIBUTOR
  • 4,750 POSTS
ok when you say low idle, im assuming you are talking about driving in overdrive just barely giving it gas and thats when you feel the skip. is that correct?
May 31, 2008 at 7:04 PM
Avatar
CSPRINGER826
  • MEMBER
  • 9 POSTS
yes
May 31, 2008 at 7:20 PM
Avatar
MASTERTECHTIM
  • CAR REPAIR CONTRIBUTOR
  • 4,750 POSTS
that indicates ignition skip or lean misfire. unplug the egr valve completely and drive, if problem goes away then we can look there. when you replaced the spark plugs was there one that was fouled? if not then im afraid you have a defective spark plug or spark plug wire
May 31, 2008 at 7:28 PM
Avatar
CSPRINGER826
  • MEMBER
  • 9 POSTS
ok i will do that now this may be stupied but what exactly does the egr valve do and there was a burned out pluged which one i dont remember
May 31, 2008 at 7:37 PM
Avatar
MASTERTECHTIM
  • CAR REPAIR CONTRIBUTOR
  • 4,750 POSTS
the egr valve is for exhaust gas recirculation, it leans out the engine to help eliminate nox gas for emissions. find the fouled plug hole and we need to find out why it is fouling. take a picture of it if you can and upload it
May 31, 2008 at 7:40 PM
Avatar
CSPRINGER826
  • MEMBER
  • 9 POSTS
ok i will do so thank you for all the help but it allso loked like the plug was leaned out ????
May 31, 2008 at 7:47 PM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.