I had a 2 K buck in mine twice, the first time it was the wires for the O2 sensor cooking on the exhaust manifold up front. Where they were cooking at was almost impossible to see. I had to disconnect all the sensor underneath (knock sensor, engine temp. and O2) and pull the harness up to get to the spot for repairs. The second time it was an O2 sensor that was fairly new.
I had a crappy idle, most of it was the ground for the TPS. I had to peal back the covering on the harness on the firewall until I found a splice that was loose.
They say initial timing is important, you can be one tooth off and it will run OK, sort of. Search indexing the distributor. If you replaced the cam indexing can even be more important.