Backfiring tru intake/TB unit

[matt sorrentino]

hello guys yesterday my 94 c1500 350 TBi started to backfire tru the TB unit when in overdrive and open throttle. It would be one single loud pop it bogs and then pick back up and be on his marry way. I already lined up new spark plugs and fuel filter. Wires are less than a year old. Anything else I should look into? I will change the spark plugs when I install my headers Friday.

Thanks in advance

 

[jkeaton]

Timing.

 

[Amgta5]

I had the same problem and it was the timing.

 

[Rusty Nail]

At what speed, exactly? 42-43 m.p.h.?