misfire
 

I have a '97 f150 (4.6 L - 8 cyl) that for the past 6 months has run rough and come up with cylinder 2, 4 7? misfires. The plugs and wires were changed 5 months ago. It was fine for while. Then misfire happened again. We replaced a faulty wire. It was okay for a while. It happened again (check engine - running rough). My mechanic told me one of the ignition coils was gone. I replaced both. It ran okay for a weeek or so. Same problem again. Mechanic said bad wires (again) so I had them replaced again (3rd time). I drove about 15 km and the light came on again(this was yesterday). I want to drive this vehicle (which I loved up until recently) off a cliff. I've had two mechanics look at this #1) auto shop teacher at the school I teach at and # 2) the top guy in town. Neither guy can seem to figure this out.

HELP ME !!!!


Dave

RE: misfire
 

PCM issue? Maybe coil driver not working properly.

RE: misfire
 

i had this same issue with my 97 f150 as well. the ignition cap or coil cap ( what ever that rubber distributer is on the top of the engine ) was some how getting water in it and the watter was leaking into the holes were the spark plug wires plugged into. i just bought a new one and installed it and the problem was gone. i also replaced my wires and coils just like you. no mechanic could find the problem on my truck either. the way i found it out is i got fed up, poped the hood and just started pulling wires and plugging them back in untill i saw a diffrence in the way it was running, as i was pulling on a wire i noticed a bunch of water come out . at a closer inspection i saw the crack and knew right away what had to be done.. take your truck to a car was, spray the engine down then wait for it to dry. then pop off the wires one at a time on the distributer cap ( if thats what its called ) untill you find one that is holding water, if you see water, then thats your problem. if no wter ... then its somethign else.

Hope this helps

Thanks

Dan

RE: misfire
 

i have a 86 f150 that had a miss like it wanted to turn of or would idle real high and then idle real low. It would go up and down and some times i would have to keep one foot on the brake and give it a little gas to keep it on while stopped at a light.

i changed the M.A.P. sensor and fix the problem...this had been going for the pass 3 years and now it purrs and i get better mileage...