Ok as the topic states, i just put my engine back in, in ran in like a safemode or something with a check engine light, once that cleared it started misfiring like no other, will run ok, say at like 3k RPM, then bog down to 1.5k bogging terribly, then run fine, then back to bogging... Checked the code and thats what came up, replaced the plugs, plug wires and O2 sensor, now frankly, im at a loss...Please any help is appreciated.

I have a 97 z24 and i had the same problem anything under 2000rpm it misfired like crazy !!. I had the engine light come on if it just sat there idling for a while. The code was a random misfire. I brought it in the the mechanic and i ended up having a bad valve ! therefore low compression. I would say do a compression test accross the cylinders and see what you get. I decided to just replace my cylinder head !