1996 Rodeo p300 error code

My son's '96 rodeo had a p303 error code and a check engine light. I replaced the coil pack indicated and it ran fine for a week or so. Now it bogs down with no check engine light but when I scan it comes up with a p300 multiple random cylinder misfire. I need to drive about 90 miles to his school to fix the vehicle. I was wondering what would be the suggested parts to take along to make sure I can get it running. Thanks:screwy:

Plugs come to mind. How old are they?

I replaced them about 8 mos. ago. What other probs could there be that would cause a multiple cylinder random misfire?? Thanks

vacuum leak, injector problem etc...