bad miss
Lead Driver
Joined: Nov 2002
Posts: 9,556
Likes: 43
From: Concord, NC
A compression test will show if a valve job is needed. What do the plugs look like? Have you pulled codes from the computer? I would do that to start with, it may point you in the right direction. http://fordfuelinjection.com and then go to "Getting Codes" on the left side of the screen. They also have definitions of the codes should any come up.
Hotshot
Joined: Oct 2002
Posts: 18,488
Likes: 22
From: The Big, Oregon
Welcome to FTE!
A common problem with these engine is a tendancy to crossfire, and blow a hole in the top of the number 8 piston. What happens is that cylinders 7 and 8 fire right after each other. If the wires for these two cylinders are run right together, they can cross fire, and fire the number 8 cylinder too soon. The first test I would run would be to pull the wire off #8, ground it on the manifold bolt, and then start the engine. If it runs the same, check the compression for that cylinder.
A common problem with these engine is a tendancy to crossfire, and blow a hole in the top of the number 8 piston. What happens is that cylinders 7 and 8 fire right after each other. If the wires for these two cylinders are run right together, they can cross fire, and fire the number 8 cylinder too soon. The first test I would run would be to pull the wire off #8, ground it on the manifold bolt, and then start the engine. If it runs the same, check the compression for that cylinder.
