overheated buick regal

I have 92 buick regal gs with 3.8 that someone gave me.It jumps and jerks when u go up hills unless u hold the gas down the cause of this is because the car was driven until it overheated and shut off. Now the car has a miss in it and I pulled each wire off coil packs while it was running and u get a change in engine sound with each one except #3 on coil pack it sparks like crazy but has no change in engine. I have changed plugs and wires but it still misses until u hit a certain speed around 50 then it runs smooth. I was wondering what could I do to fix this? Any help would be appreciated. THX

Welcome to AF!!

The first thing you need to do is run a compression check. If it was run like you indicated there is a possibility of a cracked head. Do you have a check engine light? If so, pull the codes and post here. If not then the compression check should tell you if you have leakage between cylinders. Usually the symptoms you describe are due to a crack in one or both of the heads.

No,my check engine light is not on could it also be the headgaskets?

Yes, it could be the headgaskets. As GTP stated, you need to do a compression test. Also do an injector balance test. If the injector in cyl-3 is way off from the others, you may not be getting any fuel to that cylinder. Any other suggestions before doing these 2 things would be wild speculation. An engine needs 3 things to run: fuel, spark (which you have) and compression.