I have a 2001 Ford F150 with a 4.2 L V6 engine with 137,000 miles on it. for the most part I cant complain about how well this engine has done for me. I have kept up with the maintenance on the vehicle, changed oil, tune ups, ect. I have also already changes the Air intake Manifold Bolts and Gaskets when they were leaking. anyways on my way into work this AM, My truck started to run bad. It cranked and idled in park fine, It ran fine for about 20 miles, and then it lost power and started missing. It only does this when I am trying to maintain my speed. If I jump on it the vehicle accelerates normally but on occasions I hear a thump sound(almost like a light backfire) when I first push the accelerator down, but then it gets on down the road as usual. As I try to line out and hold a speed that is where it goes down hill. Also The Service Engine light comes on and blinks for a min and then If I let off the gas and just coast along the engine light goes off. I am baffled by this. Any problems I have had in the past the engine light came on and stayed on until it was reset. Anyone out there have any Ideas. I was thinking I may have a bad plug or plug wire. I had a similar issue with the motor before and the sheath of one of the plug wires had melted onto the manifold and was arcing off on the manifold. Have not had a chance to check it out, but would like to know what you guys think? thanks


Brad Hall

 

I had a similar sounding issue from a '98 F150 4.2 auto. I had decided to replace the wires and plugs when this happened. While replacing the plugs, I found one of them less than finger tight. Apparently, it had backed itself out. Could be simple as that...

j