New to the forum but I've read most of the threads concerning misfiring.

So here is my situation. 2001 F150,5.4L,4x4, 66K on the odo, I live in San Diego so its had very limited exposure to winter and I've used it but not abused it (much).

Last week my wife drove it to work and said it was running rough and the service engine light came on. Being well aware of the COP fiasco I went and got the truck from her, plugged in the code scanner and came up with a P0307 #7 cyl. misfire code. I pulled the COP and checked it with a multimeter and got what I would consider bad reads. I replaced the COP but the plug looked fine so I didn't replace it. Truck ran fine so I called it good it sat for 4 days since we were gone for the weekend and I don't drive it to work most of the time.

FF to this morning when I got in to go to work and it started acting up jumping around misfiring and the service engine light came on and then went off. It seems to do it worst between 1500 and 2500 rpm. I took it home and had a pending code (light no longer on) of P0307 again.

I'm wondering about it being an injector now but why only one cyclinder?
My plan is to try the seafoam thing (not a real believer in the snake oil thing but I don't think it can hurt anything) and then replace the fuel filter. If its still acting up I'll throw a new plug in #7.

Any ideas on where I should go from that point? Should I replace the #7 injector? Should I replace it with a new Tacoma?

 

Find someone with a scanner that reads mode6 and a tech that knows what he is looking at. If you have not cleaned your MAF, I would. Leave the Seafoam at the parts store.

 

I had the same problem...just make sure there is no condensation in the wire that you plug the #7 cylinder back into thats the only reason you should have 2 bad reads in a row!
~Phil

P.S. NEVER trade a real truck for a TOYcoma

 

Did You Resolve Your Prob, Im Having The Same Issue, Advice Would Help!

 

Could be a few things that I can think of. You have to pull the boot and grease the entire inside w/dielectric grease - this guards from moisture buildup that will kill the coil in no time and sitting for that length of time - it's a possibility.

It's also possible that the unburnt fuel that went thru that cylinder before the coil was replaced cause a pre -mature fouling problem with that particular statement.

While the boots are removed, you check the spring to make sure it fully slid over the blade @ the bottom of the coil. From experience, they aren't always attached well.

You could have wire chaffing in the harness which can compromise a coil - short it out.

You could have purchased a bad coil. Even a new OEM coil can very well be bad or weak. There isn't a coil manufacturer out their that can get away from that possibility.

Tundra ? Not a good idea unless your looking for problems that are much larger in scale.