92 B2600i idle problems
 

Have two 92 Mazda Pickups. On the B2600i 4WD its always had an idle problem. Starts cold and runs about 2500 rpm until it warms then down so low it shakes. Had a shop scan it and he said the O2 sensor was bad as well as the computer. Replaced them both with no results. Now, get this. I found a wrecked PU with a real low mile engine and bought it. It was a roll over with about 45K on it. Started the engine before I pulled it and it ran great. No problems with idle or anything. Swapped the engine into the other truck along with the computer and mass airflow sensor from the wreck. I still have the same strange idle problem! Can't think of what to do next.

On my B2200 2WD I just put a new engine in it and noticed what I think is a condenser on outside of the distributor. Its a little square plastic box with a wire running to the coil, and the wire is broken off even with the box. Auto parts stores cant seem to match it. They keep coming up with one that is actually like the one on my B2600i. That is a completely different engine, actually it a Mitsubishi engine. I'm wonder how important this is and if I can use a generic condenser. Any thoughts out there?