Hi all, I've had a running problem with my F-150 4WD that has recently gotten worse. I recall reading a post a while back regarding an issue with these trucks that was more-or-less common, i.e., the shuddering or rumbling that happens between gear shifts.

A very helpful moderator explained the solution in detail (I forget who) and as I recall it had to do with a misfiring or otherwise faulty ignition coil, which did not show up on a diagnostic examination.

I want to take the truck in tomorrow to the shop but I wanted first of all to be sure I and they know exactly what the problem is (I recently had them run a diagnostic and the misfiring coil thing did not show up).

The proposed solution is already on this forum somewhere, I just need someone to direct me to it! My aim is to take a printout of the solution directly to my mechanic.

Any help here would be fantastically appreciated!

-Mike (from central Ontario)

 

Need more details -- what year & engine??

 

Yes, of course. It's a 1999 F-150, FWD, with an 8-cyclinder, 4.6 litre engine. Shudders occur roughly between 40-50 km/h (second to third gear shift?) and anywhere from 100-120 km/h (third to fourth gear shift?).

 

Wrong forum. This is the 2009-2014 forum, but yeah, it sounds like a plug/coil type issue to me...

 

moved to the 1997-2003 forum.

good luck on your quest!

 

Just looking for codes with a Scanner will not reveal the faulty coil.
Tell them they must access mode 6, test 53 to look at each cylinder misfire monitor.
The one with the high count is suspect.
The reason why there is no code set is because the misfire is not permanent or a hard fault but comes and goes. The normal misfire record is cancelled each time the misfire clears.


Good luck.

 

Thanks a bunch! I'll take this info to my mechanic and hopefully I can solve this problem once and for all.

I'll let you know how it goes.

Cheers.