Ford Forums banner

1 - 2 of 2 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter #1
My son has a 05 ford f150 4.6, he was on the interstate headed to work and the check engine light came on. It is running rough at idle, like it has dropped a cylinder. We scanned the codes and got p0303, p0308 and p0300. So misfire on #3,#8 and random. I changed the cam sensor, fuel filter and cleaned the throttle body and it didnt help. Im at a loss as to where to look next. Also, it had blown the plug on #3 a few months back, i had it tapped and coiled with a new plug and a new cop. So im doubting its the cops or plugs. Also being its on both sides of the engine. Is it possible for both vct's to go out at the same exact time? Thanks!
 

·
Super Moderator
Joined
·
8,277 Posts
First thing I'd do is inspect the plugs and verify they are actually firing. Then try moving the coils to different cylinders. if the problem moves with the coils, there's your problem. If it stays with the cylinders, try swapping injectors. If it still stays with the cylinders, try a compression test (or you can try that right off the bat multiple possibilities). Had a similar problem a few years ago, turned out a had a very minor intake manifold leak on a Pontiac that was weeping antifreeze into the intake.
 
1 - 2 of 2 Posts
Top