I have a 08' f150 4.6. For the most part it runs good. The engine just has a little miss in it at idle. I have changed the fuel filter. My next step was spark plugs but wouldn't that trip the check engine light?

 

Maybe the injectors. That would not trigger the check engine light, right?

 

what you can do is unplug the coils one by one while it is running. if the idle gets worse then that cylinder is contributing, if the idle doesnt change you know what cylinder is causing the miss. then you need to check for spark, injector flow and compression on that cylinder to find whats causing the miss.

 

Check for a possible vacuum leak. It would cause a miss at idle but go away off idle.

 

This

 

I thought the same thing.

 

Ok. Thanks a lot guys. Geez how many different vacuum lines are they?

 

I have the same dam issue.. haven't figured it out yet

 

What have you done to fix it that didn't work? I am trying to get straight to the source, ya know what I mean?