Frustrated 2000 5.9l 4x4 engine problems

[Brett_chomyn]

A little while ago my throttle body started a somewhat 'hissing' and sounded like a whooshing when the valves opened, also it was louder when it was cold and it lessened as the vehicle warmed up. And this spring it started loping or missing while accelerating, and if i accelerated hard id get a backfire, not in the exhaust but in the intake manifold region. I sprayed out the throttle body with intake manifold cleaner, and it ran great for a few days and the problem returned. The pcv valve still clicked when i shook it but i changed it anyway. I changed the plug wires, dist cap and rotor today and while i did that i sprayed the throttle body out again. Air filter is a K&N and looks clean. There is some vapor or water that comes out the exhaust.

Now my pcv valve and hose randomly vibrate and make a good noise like something's in there vibrating around. Any ideas or tips as to what the source of my problems are. Or tips for hunting vacuum leaks. I'm going to change my tranny fluid next weekend and that would be an opportune time to try any ideas out!