And It Still Knocks!

[daniel3507]

my 4.0 has a rough ideal and a mean knock to it. been like that for awhile too. so far ive done the simple things. seafoam, cleaned MAF, fuel filter, plugs and wires, air filter, air filter. nothing seems to have helped. im out of ideas on what is making it like this. the only things left i can think of are the lower intake manifold bolts and new pushrods and rockers? any ideas? its driving me nuts.

 

[rags]

If by "knocking" you mean predetonation or valve rattle on a pull? It is probably running lean, I found that the main cause of this is the lower intake gasket, My 94 4.0 rattled bad on a pull and i tried everything same as you. Then i developed a small antifreeze leak from the back of the lower intake and replaced the gasket. It hasent made a noise since! and that was 2 years ago, and seems to have a bit more power.

 

[daniel3507]

i'll check for vacuum leaks around the gasket. im pretty sure thats what it is though after doing some reading. number 5 plug had some oil around it and apparently thats a common sign