bigblueford

Ok so last thursday i was driving the truck, and all of a sudden i got a weird stumble. pulled over, and my intake cone was half way off. i put it back on and it ran fine all day. later that night, it did it again. i got out looked at everything, all seemd fine. i started driving home, and the truck just started misfiring, flashing the CEL. so i pulled over and turned it off. my buddy came with a code scanner, we checked it, and it said i had 4 codes

- running rich
- running rich
- evap leak
- misfire cylender 3

i always had a running rich, bank 2 o2 sensor throws a code, and evap leak (cant figure it out)

so i got it towed to my mechanic, and told him to fix it.

he replaced the front 4 spark plugs and boots on the front of the motor.
he called me and said im ready to go(only charged me 100 bucks)

so i went and got it, and its still doing the same thing!!!! CEL blinking and all. so i brought it back to him, and he said change the fuel filter real quick, so i did, and the filter was very dirty, but its still misfiring.

it seems to idle fine, a lil bumpy at times but almost fine. but the moment you give it gas it starts to stumble BAD!!!!

Any ideas?

clogged injectors?
fuel issue?
intake leak?

anything will help. its at the shop again, but i have a feeling this is going to be an ongoing problem

krock918316

I would check the coil packs. I eneded up having to replace all 8 of mine by the time I got to 100,000 miles on my old '02 F-150.

bigblueford

im at 140000 on a 97 f 150

JRV

I believe it will be your coil pack on the driver's side. The easiest way to tell if it is in fact a coil pack will be to swap coil packs around, and scan to see if the misfire has moved to another cylinder. If it has, you have obviously found the problem.

The exact thing happened to me - cyl #3 actually - and this is what I did. Same flashing CEL, same stumble. Replaced that coil pack with a new Napa unit for $50, and she runs like a top.

*edit* Your truck (and mine, 98 4.6) should only have 2 coil packs. I think what krock918316 is referring to is COP's (coil on plug), which my truck doesn't have, and I'd assume yours doesn't either.

bigblueford

just looked into it, i have COP

krock918316

What size motor do you have?

bigblueford

5.4 this problem is confusing the heck outta me and my mechanic

krock918316

I would swap that coil pack on cylinder 3 with another one, and see if the problem follows. If it does, you've found your problem.

JRV

He's exactly right. Its the same concept as when I switched my coil packs around. If the misfire doesn't move to the cylinder you swapped, next step is to see if your wire is bad. It could also be an injector. My money is on that COP.

I'm surprised you don't have coil packs! Maybe thats just one of the things between a 4.6 and a 5.4 I guess.

krock918316

Those things go bad easily......we're a Motorcraft distributor, and we usually have between 250 and 500 on the shelf at a time.