mileslong

New member here, same problem. Started last night.

2008 Ford F150, 115k on the clock. 4.2L V6.

Was shaking upon startup.. I started to drive it and as I would accelerate it would sputter and almost try to backfire it seemed. Had very little power while accelerating.. and was shaking still pretty bad. I went to O'Reillys and put a new air filter on.. thinking it wasn't getting enough air, and also dumped a can of seafoam into a new tank of gas. Was still shaking...The check engine light came on while driving back to the house as well. I parked it and wanted to let the seafoam sit in the injectors etc.. overnight.

This morning the problem seems to be gone... I tried to recreate the problem and can't. I had O'reillys check the light and see what popped up and it said cylinder 2 misfire.

I'll keep an eye on this thread, and update if the problem comes back and hopefully post a resolution if it does.. for now seafoam seems to have cleaned whatever and alleviated the problem.

mileslong

And...... it's back at it. I'm going to work on it this weekend. I suspect the COP and/or plug. Will post an update.

mileslong

Ended up being a bad coil pack. Replaced it..runs and drives just as it did before.

Craig4937

Eric, This was the issue!! I filled the truck up and put in two bottle of techron and did what you said, Heat cycle and cool down...It took about a half tank and started running better. Then I installed the fuel filter, I drained the tank side out of the filter and it was dark brown. it looked real bad but the engine was clear...

So Thank you, everybody was all over the place! so again thanks...