altima engine vibrations

[merlin80]

Hey, I have a 1994 altima, with some high frequency engine vibrations that are transmitted to the steering wheel and flor as well.

Some background:It all started with a bad distributor (I had no ideea in the beginning it was a distributor) - the engine started running on three pistons every once in a while for about two minutes, and then coming back to normal. I changed the distributor (to a reman) - problem disappeared however some vibrations remained. Changed distributor agian - same thing. Injector cleaning fluids (several bottles), new motor mounts - no change (the motor mounts did help a bit - but the vibrations are still there). It looks like the knock sensor erro code is on and i hear some rattle coming from the timing chain (probably the tensioner problem that has benn mentioned on this forum before). My mechanic made me change the front axles as well though that of course had nothing to doo with my vibrations since i get the vibrations even at idle.

I havent found any vacuum leaks. Anybody any ideea about what could be causing it? I don´t think the knock sensor should have such an impact - and I am reluctand to swap more parts in vain (there are already too many $ in that car). And if this wasń enough the car is also high mileage (160k)Thanks a lot!!!!