So my 94 5.8 e4od has been running crappy for months. I changed out tps, iac, replaced all vacuum hoses. EOER test threw a 311 code is why I focused on thermactor system. Finally found that my TAB air valve solenoid was bad. Was ready to order a new one when my engine started sputtering so bad it would die while driving. Just replaced bad cat. Now it will start fine until it warms up then while driving it sputters and backfires and dies. I let it sit for a while and it starts up and drives for about a mile and repeats sputter backfire and dies. Any suggestions? Cap and rotor? I'm stumped. I don't think the bad TAB solenoid would cause it to backfire and shutdown? Help...