Car won't accelerate and idle is a little off

What is your question?

My 1997 Oldsmobile 88 won't accelerate to over 10mph and even getting there is rough. When idling it sounds a little off but not bad. Check engine light is on and car is throwing a misfire code (P300 possibly). We have changed the fuel filter, fuel pump, spark plugs and wires, and the coil packs. We are lost as to what else to try please help!!!

What makes this problem better or worse?

It's worse when trying to accelerate

How long has your 1997 Oldsmobile 88 had this problem?

1.5 weeks