Idle Issue

Like stated, 1992 Subaru Loyale 4 door wagon with 4 wheel drive.

I just recently put some parts in the car. I put new ball joints, exhaust manifold gaskets, and a new injector on the TBI. Ever since I did all of that, the car will not idle well sometimes. (She never did idle smooth, but it was a consistant not smooth.)

Sometimes when you push in the clutch to roll up to a stop sign or street light, it will idle fine. It will vary a bit, but it idles. (It did this before to) Sometimes though it will all of a sudden just drop and the car shakes horribly and if you don't feed it a little throttle, it will die. It starts right back up again and will sometimes idle or will sometimes fall flat again.

I did not take the TBI off, I just removed the top plate, removed the old injector, and put the new one in. The new one came with a new o-ring so that was new also. It is strange how it will idle sometimes and not others. It seems like it will idle better cold then warm which leads me to believe that it is getting too much fuel, but why only sometimes?

Or could there have been a bigger problem at bay and by putting a new injector in, now I have another issue? I was going to run through some tests on that air control valve (or whatever it is called) to see if it falls within specs and I was going to just go over everything again to make sure I didn't accidently disconnect a vacuum line or something.

Any other advice or suggestions? I have been driving it like this for about a week because my girlfriend just bought a 97 GMC Jimmy and I have spending my time on that and neglecting my Suby!