I have a 2003 F 150 supercrew with 5.4 and 180000 miles. recently (5000 miles ago) replaced all plugs and 3 coils. no codes showing. When I am going a slow speed like 15 mph then slowly accelerate I feel a slight what feels like a miss. when I get to about 40mph it goes away and never shows up again til I repeat above situation. I have checked all vacuum hoses. air intake connections. I thought I may have water in fuel but I think that would miss all the time. Anyone have any Ideas what I can check next.

 

Clogged cats? Bad plugs or wires?

 

With the way it is missing, I'd suspect the plugs and have to verify which were used first. Sounds like an Autolite issue. You not posting specifics, so it's just a hunch. It's missing in an uncommon way as well for both V8's. In which support the plugs used theory.

 

I used Motorcraft AGSF-22W plugs. I got them installed at my son in laws shop in Chesapeake Va. 120 miles away. Only 3 shops in this small town have diagnostic scanners and cannot get me in for a week. Ford dealer wants $139. just to scan. guess I wait a week or drive to Chesapeake.

 

Wow hat sucks.... no Autozone, O'Reilly, or NAPA around? All 3 of them will scan for free here.

 

Have auto zone, napa,advance and Oreily and they will scan for codes only. I have a code scanner and there are no codes.