2000 nissan xterra rough idle

[AkXterra]

I think i have tried everything nothing seams to help except for when i unplug MAF sensor car runs perfect i cleaned it checked with a voltage meatier check out good. New tune up (wires plugs rotor cap? )ne timing belt pump everything tried to smoke out vacuum lines no leaks but there are 3 vacuum nipple like in the back of the manifold i know one goes to the preasure regulator the other one i forgot but its hoocked up too third one i cap it off have no idea where it goes new fuel filter, car becfiering at idle when hot, but when i unplug maf its perfect im stuck can a maf still be going bad even if it checks out good? And ignition timing is set and good at 15°btdc
Or is there idle relearn procedure for idle. The distributor was replaced at 80k miles because bearing went out and massed it up car now has 120k but distributor seems to be working good with ne cap and rotor, the only code is knock sensor but its probably due to rough idle and a little bacfire

[Desert Rat]

Maf can go bad. Any codes besides knock sensor?

[AkXterra]

Yesterday one came up a vacuum cut bypass valve i will look into it today can it be causing it ?p1491 i think thats it. So even if maf checks out good it can still be bad or is going bad?