454 backfires

[txguard88]

I've got a 1978 Chevy Big Ten. It's got a 454 and a TH 400 trans. Not sure on the rear end. I just replaced the coil andignition control module this weekend. I drove it into work this morning and around 2200 rpm the Rpms started jumping sporadically. After work and after adjusting the idle air mixture screws it was still doing the same thing but at higher RPMs. It also started backfiring on the way home. Any ideas what this may be? I've already checked the wires on the distributor and all are correct.