Hi. I have a '91 F-150 5.0 302. From what I've gathered on the internet, the firing order is 13726548, and I replaced the plugs, wires, cap and rotor. Now it sounds like my engine is missing on about 5 cylinders. I double checked the order several times, and I arranged the wires according to this picture. What could be the cause of this? I didn't feel any exhaust from the plugs, either, so they are all tight.

 

try 15426378

 

Worked like a charm. I guess the question now is why would a Ford document put a different firing order than what is actually used on my engine?

 

Some of the high output 302's in the late 80's & early 90's used the 13726548 firing order ( which, btw, is the same as the 351W engine.) Some repair manuals don't define this clearly.