Hi all, I'm a shade tree mechanic at best. My 1997 F150 4.6 Windsor is running rough as hell. At higher speeds she's sort of okay, but with reduced power. At idle she could scramble an egg in its shell. Cylinder 7 has low compression. My novice guess is that if this were a bottom end problem it wouldn't run very well at any speed. Since it runs barely okay at higher rpm then I guess, GUESS, that maybe a broken valve or valve spring? Will I be able to see a broken spring if I remove the valve cover? If it is a broken spring do I have to remove the head and send to a shop?

1997 F150 4.6 Windsor 175000 miles.

 

p.s. - I'm the shade tree mechanic. I live in Texas but am broke down in Torrance, CA. If you know of a decent shop in the Torrance or Los Angeles area, please let me know.

And, do you think this truck is even worth all the money and work I'm putting into it? Should I just go buy another truck?

So far I've replaced the #7 injector and the coils.

 

How bad is the compression?

Did you replace all the coils, or just on 7?

Any vacuum leaks? Check the PVC elbow on back of intake.

 

Agreed with Holicori check for vacuum leaks

I trust while you had coils out you pulled your spark plugs and inspected them?

Did you do a fuel system pressure test? You could have a clogged fuel filter.