I have a 1990 F150 5.8L w/ 155000 miles. I have only one problem - rough idle. I've done all the standard stuff (cleaning etc) and then I noticed a vacuum leak. What I call the throttlebody (where the two air hoses hook on and what the throttle cable is hooked to) seems to be the problem. I can spray carb cleaner around the height of the bottom of the EGR into where the throttle body bolts to the plenum and the truck will almost die. I replaced the gasket and the same problem was there. I took it back apart and bought some liquid rubber gasket and put it on both sides of the replacement gasket. But now I still have the same problem. Is the throttlebody warped beyond repair? Is this a common problem? What do you do to fix it?

Thanks for your help.

John D
jwdenney(No Email Addresses In Posts!)