Took 3 tries to figure out why that Ford 5.4 kept missing

Had a 08 F-150 come in last week with a cyl 4 misfire that wouldn't clear no matter what parts I threw at it. Swapped coils, plugs, injectors and it still ran rough until I noticed the intake gasket was crumbled on that side. Has anyone else had a vacuum leak act exactly like a fuel problem on these modular engines?

2 comments

2 Comments

wyatt_green28d ago

Did you check the PCV elbow? Those dry rot and cause weird vacuum leaks.

the_kelly28d ago

Literally fixed my idle issues swapping that exact part.