After reading the entire thread twice, I have two inputs to hopefully steer you towards a conclusion. One is free, the other is expensive (hence try the free one first). There is a small hose "T" that plugs into the top of the frame of the TB where it mounts, is that seated properly and clean inside (no debris entered it when you swapped the TB out)? Second, could you have gotten a defective TB?. Its about all I can come up with, hope it helps.