I would make a code reader if I were you. Turned out to be the best 5 bucks i ever spent.
I had a similar problem, just rebuilt my turboII motor, streetport... It started up but flooded and backfired like a bitch.
Mine threw a code saying there was a problem with my thermosensor (on the back of the water pump). When the sensors bad or the circuit is cut, the ecu dumps fuel into the motor as a "fail-safe" so you don't detonate, no matter what your temps actually are. I fixed that, and my car ran better than it did before the rebuild, streetport, and emissions removal... go figure
It could be that, your throttle position sensor, bad injectors, or something else.
I can't pinpoint it, but a code-reader could definitely narrow down the possibilities for ya