Hey, my 94 chevy s10 4.3l v6 has a major backfire in rebuilt tbi unit, spark plugs are black, o2 sensor is black, plugs and wires routed correctly.. new fuel pump and filter installed. this happened after i rebuilt the tbi, i sprayed quite a bit of carb cleaner in it to clean it out, and "seafoam" in a nearly empty tank, then put about 2 gallons of gas in it. now my truck will not stay running and has major backfire. Before i rebuilt the TBI unit it was running extremely rough, had no power when accelerating and would sometimes stall. I have changed nearly every sensor already. Check engine light is not on. any ideas?:con fused:

 

That happened to my s10 bad cap and roter put new stuff in ran great