This board has helped me a lot. I try to contrbute by occasionally posting things that happened on my 92 5.0 as I believe it may help someone fix or avoid a problem.

I noticed my idle rpm getting higher month by month. It also became rough. Finally the engine quit. Turned out to be the intake manifold bolts had worked loose and the gasket blew out, causing a major vacuum leak. The shop said it is fairly common on 5.0 engines. I suggest re-torquing the bolts to prevent this $300 repair. Hope this helps someone.

 

A good point laneman about checking the intake bolts. After buying my truck, I soon noticed a rough idle miss along with it "bucking" in gear with any kind of acceleration. After doing all the typical cure's(plugs, wires,etc.) I took it to a local shop, where they told me it was the injectors. After I took the upper intake off, the real culprit was the Torx Button head (only one)that sits in between the upper intake runners on the drivers side. Whoever had worked on it before had evidently dropped the original bolt down into the lower intake sludge and decided to just grab another one. Well that "other one" was a 1/4" longer, so that bolt never torqued up the intake, just bottomed out making them think it had drawn down the intake, which duh, caused a vacuum leak! Although my vacumm problem was due to an @sswipe's stupidity, I was able to learn alot about my engine and saved some $$!

 

 

easiest way to check for a vacuum leak or intake leak is with WD-40 or starting fluid . start the truck and spray around vacuum lines and intake gaskets . if you have a leak when you spray near it the rpm's will increase .