I have a 92 f-150 flareside with a 302 5.0. Will a bad head cause it to run rough, especially when it shifts into overdrive? It shakes the whole truck. I have replaced the IAC and Dis. cap and rotor. I also think my rings are burnt. I have dump over where my air filter is.
Also my MPG is around 10 MPG.

 

A bad head or valve will cause the truck to shake quite a bit. I had that happen to me. I did it in the 800-1500 rpm range, and it was the worst in OD. It didn't shake on the highway, though. You can read about it in this forum. I think the title was "1990 F-150 Shakes Between 1000-1500 RPM." There are a few things that you can do to check this.

An air leak in the plenum or throttle body may make it shake a bit. Also, bad motor mounts will cause shaking.

Are there any other specific symptoms that you are experiencing?

 

Bad gas smell in my exost, blueish smoke. My #8 cylinder files down the sprak plug pretty quick, so I pulled the wire while it was running and saw no difference in how it ran. You described exactly what it does. That is what I was thinking it was. I geuss I need someone to take a look at it to what it cost to fix. I hope not much, hurricane Kat wipe me out pretty good.