Older Tippmann 98 Question

I'm sure this has been covered before but I was hoping that someone here can help me figure out why my 98 spits out anywhere from 3 to 6 balls once in ahile when playing. I bought this one and an A5 last year for my son and I to play with but would like to get the 98 straightened out before we go PBing here in a couple weeks. Let me know what you need to know if I didn't give enough information. Still very new to the sport but look forward to getting to know the in's and outs of the sport and equipment..

I would check the detent as well.  If you remove the barrel you can look into the marker (make sure there is no air connected!) and see if the detent is worn out or broken.