I agree with the other replies, have it scanned by O'reillys auto or another auto store that does it for free, that is your starting point,then we can go from there, it is a process of elimination, my problem when i read the code from the scan was a P0304, which was the #4 spark plug, I took it out and examined it and found a dark burn spot on the ceramic insulator, the plugs I had on the car where E3 plugs, I went and got new AC/Delco iridium spark plugs , installed them, and it runs great, but get the scan done first. it could be something else

Considering the age of the vehicle, it could also be a failing fuel pump. A scan will help us narrow it down. If you get it scanned and the trouble code comes back as P0300, ask if they have a fuel pressure gage you can borrow. That will be the next test I will ask you to do.