99 GT problems, hesitation and stalling

My car is a 99 grand prix gt, and I am having some issues that I'm not sure what is the problem. The car has 2 issues, the first is a misfire that only happens in third or o/d, the car seems to hesistate under 2k rpms. I've seen the service records, and it has gotten some work for cylinder #5. (reciept shows replacing of coil pack and spark plug and wire, I don't know if it was just for this cylinder if they did the whole thing) The other issue (don't know if it is related) is that the car seemed to just die on me today. It took a couple of times to start it up,sometimes it would catch then die, others it just sat there turning the motor. I finally got it started back up and it seemed the hesitation would get worse, but toward the end of the drive, it was acting normal again. Could these 2 problems be related? I've got a set of wires and plugs from Pontiac that I was going to put on anyway, but searched the internet and I think it might be something different. (fuel pump related?) Any suggestions. I'm not a mechanic but have done 99% of the work on my other car, so hopefully I can figure this out as well.

Thanks, and sorry for the long post.

edit: also, there is no check engine light so I assumed there was no codes unless some kind of stored memory code, but haven't checked with a scanner. Also, the car dying just started happening.

If it has cheap aftermarket plugs and wires on it (or the originals other than cylinder 5), do your tune-up first. If that doesn't help, then you need to do a fuel pressure test. Another thing to look at is the MAF sensor. They can cause drivability issues and stalling/hard starting without tripping a CEL.