Running rough under load
Senior Member
Joined: Apr 2004
Posts: 13,679
Likes: 84
From: missing Texas...
SVTis4THUNDER..... I posted a relative same problem yesterday on my '99 f150 4.6L. I also have a intermittent stumle upon accelleration. Otherwise runs perfect at idle. No codes as of yet.. Changed out both coil packs,plugs,wires,EGR solenoid, fuel filter,TPS unit, crank position sensor. MAF wasn't dirty, but cleaned it anyway.. I also have a K&N air filter installed and has been in for quite some time.. I've ran many OHM checks on different components and seem to be within parameters.. Come fellow F-150 owners, I'm running out of ideas... Thanks for leting me join the site...
#1 thanks for bumping a seven year old thread
#2 did you use motorcraft plugs, coil packs and plug wires? diaeletric grease?
Junior Member
Joined: Oct 2011
Posts: 2
Likes: 0
Tarajerame,
I used motorcraft plugs, and autolite premium plug wires, no dielectric grease.. Installed 2 new coil packs.. (not motorcraft) but still no change.. I comparatively tested old coil packs w/ new and found everything within book specs.. I changed packs for nothing.. Any thoughts on plug gap being too wide ?? calls for .052" to .056.. I set them mid way..
I used motorcraft plugs, and autolite premium plug wires, no dielectric grease.. Installed 2 new coil packs.. (not motorcraft) but still no change.. I comparatively tested old coil packs w/ new and found everything within book specs.. I changed packs for nothing.. Any thoughts on plug gap being too wide ?? calls for .052" to .056.. I set them mid way..
Senior Member
Joined: Jun 2003
Posts: 643
Likes: 0
From: New Jersey, USA
I have the same problem with my 04 L (brief stumble when stabbing WOT) except there's a kicker... it only does it when it's below 60f outside. Changed the MAF/IAT/TPS/EGR to no avail. Been doing this for two years now. Ford dealership hooked up there diagnostics system and couldn't find any problem. Could a bad coil pack be sensitive to the outdoor temp?