Hey, after 30 plus years of Chevy's, I finally bought a Ford but need some help since it is so different than what I am used to. Mine is an 87 F150 with a 5.0 liter v-8. Wasn't running when I bought it. After complete tune up, oil change, high pressure fuel pump and battery it is running, but have two lifters tapping and it won't idle. Can deal with the lifters, any ideas why the idle is unsteady, bounces from about 500 rpm to 1200 and back down. Have checked all vacume lines and they appear to be okay. Have discoed the tpi and no change. Any suggestions? Oh, by the way, it was a single owner with less than 75,000 miles.

 

Look for Vacuum leaks. Thats a pretty old truck expect to have to work on it some. The gasket between the plenum and intake manifold is prone to failing after many years check that for leaks that would cause that problem..

 

Thqnks, I just pulled the plenum, going to have injectors cleaned while I can see them. Will check all vaccume lines again.

 

Dumb question! How old is the gasoline?

I'd put a couple bottles of Gumout with regane in the tank and run it through to clean things up a bit.

 

Well, it wasn't a bad lifter. It had a bent push rod. Not sure what bent it. Will be replacing it tonight and run compression check to see whats going on.

 

Thanks for the update. We are interested in knowing how problems are resolved.