Misfire after timing job

[Hhernandez91]

I did a timing job on my 05 I followed Fordtech makuloco video. It ran perfect for maybe 10 minutes then it started what I believe is a misfire the motor was shaking but check engine line did not come on. I was eventually able to get a code out of it misfire on numbers 3 and 7. But it only gave a code that one time it still idles very rough but will smooth out if I rev the motor. I don’t know what it could be. Any help would be greatly appreciated.

 

[whtbronco]

Vacuum leak. That would smooth out some at higher rpm.

 

[Hhernandez91]

Thanks I’m going to check for one

 

[studabaker]

+1 vacuum leak
It could be 2 issues.

Listen for the hissing. Hopefully the valve cover seated properly. The back is tricky to make sure the gasket stays. I have an 01 but probably similar. Just run hand around the back of the cover. They want a new gasket every time it's opened but if it's in good condition it will be fine to check it out. I put rtv on the entire head surface then the cover can be pulled off and the gasket stays in place. The book only calls for it at the connection of the front cover joint spot.

At least you have narrowed the misfires down to those 2.

Good job on the timing by the way.