Blazer misfiring. tryed cleaning egr valve(no help) Vaccum Lines are all ok. took cap off distributor, cleaned it. (no help) no bare plug wires. All new plugs gapped at.045. (no help) unplugged one plug at a time...when i pulled of cylinder number one plug wire...it seemed to run better:S when i pulled off all the other ones(ONE AT A TIME) it made no significant difference) awhile ago i had a fuel problem and replaced lines going into plemum, and spider injector assembly. ( fixed problem. ) my blazer was sitting in my driveway warming up(running completly fine) and all a sudden it changed sounds completly(misfire) something suddenly when out. PLEASE HELP. my only vehicle and im stumped!