Oklahoma Outlaw

Truck started a small misfire but no error codes. Added a can of seafoam and filled up. Misfire got worse in a few days started getting error codes stating inj 3 misfire and misfire during startup less than 1000 rpm. Replaced plug and coil even though both less than two years old. Weapon x sent me a new coil under warranty. Cleared codes and truck ran a little better but something still not right. On the test ride did a burnout and ran the truck hard still something not right and now dash light error flashing....also now getting more error codes incuding one with no description just a number. Looked it up and said possible wiring harness failure. So I started looking for a short since I was pulling on the wires hard when I changed out the coil. I also check fuel injector connections. The #3 fuel injector connector was only about half pushed in which I must have done clumsily. Pushed it in firmy and cleared codes. Happy Truck Happy Driver. I was really worrying after googling injector 3 misfires F150 5.4L 3V.

Just sharing a story that had me worrying and ended up being a small fixable solution.

Martian

I'm assuming you mean CYLINDER 3 misfire and not INJECTOR 3 misfire. Is the injector maybe stuck closed? SeaFoam in the tank won't really do that much. I'd recommend you try actual cleaner, such as Techron or Redline.

techrep

iTrader: (1)

And error light on dash ?? lol

Martian

Waiting for an update / answers...

Oklahoma Outlaw

I had a cylinder 3 misfire initially. After changing the plug and coil and clearing the codes I had a injector 3 misfire which Im assuming was caused by the electrical connector coming loose. Anyway all is well now.

Oklahoma Outlaw

you know...the little wrench thingy

Martian

Glad to hear it.