So i've got this '98 F150 with a 4.2 l V6 rebuild with about 50k on it. It seemes to be running on less than 6 cylinders, running really rough and having very little power. i tried some of the tricks mentioned around these boards such as removing a plug wire from one cylinder at a time to see if anything changes.

Removing the front passanger cylinder wire seemed to have no effect (or make things worse) so I'm assuming that's the problem. I removed the wire from the coil pack end, not the plug itself and it seemed to send a large spark from the coil to the wire if I held it 1-2 inches above the coil. From that I assume the coils are good. Do plug wires and plugs go bad after 50k?

 

Plugs, like any other part, can fail at any time.

If you read your codes (requires a scanner), you will know what the computer is having problems with.

That said, a spark plug costs 4 bucks.

Steve

 

I had a similar experience several times with my 94 Ranger, travelling at speed (sorta high) with slight load. With that vehicle I was able to pull over, let it set for a few minutes (sometimes longer) and everything would be fine. I later learned that this had to do with one of the sensors getting out of whack, and turning off the engine let everything re-set.

That's what worked for me. Crazy scary feeling, truck just sort of halfway shutting down while travelling around 75 MPH, yet not actually stalling! WEIRD

 

Howdy,

Your light is flashing because it is miss firing. You need new plugs.

Paul