lower intake

[deadbeat]

hey guys, i have a low mileage 2.9 that i bought out of the salvage yard and put into my truck. It has a shaking problem at low rpms, kind of like the one you get from a vaccum leak. I cant find a leak anywhere on any line or fitting, and i have sprayed all around intake and replaced plenum gaskets, but i have not replaced the lower ones, the question i am curious about is "Has anyone had trouble with the lower intake sucking air in a place where you cant detect it with starter fluid, or has anyone even had trouble like this from the lower intake gaskets?"Note, it seems to shake a lot worse when it is cold.

[rickcdewitt]

did you do a compression test when putting it together?did you pull the little plug in the harness before setting the timing?

[deadbeat]

yep, done all that
the motor runs good, it just shakes at low rpms, as soon as you touch the accelerator it shakes, but when you floor it, it quits shaking