The car was running perfect then it just started missing real bad when you start going into boost or real low rpms. No vaccum leaks, new plugs, wires, grounds, and msd box. And I was wanting to know if a coil pack could start going bad, or do they just go out?

 

Sounds like its something to do the msd box. I had an amp go bad and did the same things. Bypass it and see what happens..

 

I just put the box on trying to see if it would clear it up but it didn't