Vacuum Leak?, Still breathing, Why??? Options

[kkid]

I've been skeptical if there is some vacuum leak since the warm idle still goes up and down about ±50～100.
So I covered the air inlet on the air cleaner housing completely but the engine was still running as if nothing happened.
Does this mean there is a huge air leak or is it designed to breath the air from somewhere else????

Thanks in advance (IMG:style_emoticons/default/pray.gif)

[SLITS]

All of the items you mentioned are pre-TB / plenum and would not have an effect on the idle.

You never stated if the idle oscillates or just sometimes it's a little higher than others.

If it is a steady oscillation at idle (hunts @ idle), I would suspect:

1.) Point cam bushing in distributor is worn allowing side to side slop and the timing/dwell is changing (pretty obscure)

2.) To low of fuel pressure (lean mixture) or to high of fuel pressure (rich mixture)

3.) Injectors not flowing a same rate

4.) Trigger points could could be fouled

If it is when you come off the throttle while driving (ie, coming to a stop sign or light) ... a transient condition

1.) Throttle cable is sticking slightly

2.) Gunk around butterfly shaft in TB is not allowing it to return to same positiion each time.

Hey, just guessing at things I would check ........... +/- 50 to 100 rpm is not a major problem ... irritating, but not a great problem.

These things are not electronically controlled sophisicated engine management systems and they are old.

Anyway, read the article in the link that follows:

PBanders D-Jet Site

And bookmark it.