got an '87 turbo. idle is real rough. I've tried to adjust the adjustor in the throttle body (think that's what it's called) but it won't settle down. Help!

 

The adjuster in the throttle body is your idle speed control, but you can only adjust it after jumping a few diagnostic pins to disable the ISV. Otherwise you are just turning a screw and not really doing anything.

Define rough....

 

rough: sometimes it idles at 800, sometimes at 1000, sometimes it shimmies back and forth. Also, the enginevibrates a lot.

I had the engine rebuilt, but I think the guy botched the job, because 5k miles later, I did a compression check because it's burning oil, and two cylinders are good, one's okay, and one's terrible.

 

Well the compression isn't helping the running issues if you are fouling plugs from a low cylinder. Typically a hunting idle is due to 3 things: Vacuum leaks, Bad ISV, or a bad/misadjusted TPS. If the engine is vibrating, then either your motor mounts are shot and need to be replaced, or the guy that did your engine rebuild has your balance shafts not aligned properly. The most common mistake is to put the balance shafts 180 degrees out of correct alignment, which will cause that vibration. If he rebuilt the engine, I would hope that he replaced the motor mounts at the same time, so I would look towards your balance shafts.

Either way, the car shouldn't have running issues 5k miles after a rebuild.

 

I've put too much into this car already. Maybe I should think about giving up on it.

Ijust had the turbo rebuilt and the guy (not the same guy who rebuilt the engine) found some vacuum leaks which he fixed. It idles better, but still vibrates. Pardon my ignorance, but what does ISV and TPS stand for? Is the balance shaft something I could do myself? I don't have much mechanical experience, but my brother has some and he could help.