You know the TPS isnt set right, so why havent you addressed that further?
Is this fault RPM specific or throttle specific or combo of both, can you slowly accelerate up to redline? How fast what gear does it happen?
Im no expert on the blast, but i do know a if its a legit back fire like pops out the intake its timing related. Youve already verified your fueling soooo a carb, with TPS means more throttle, advance the timing, tooooo advanced... Pop out the carb... Hmm TPS .85v spec is .50v i bet it advances the timing too much for rpm.