I had the same problem. (post: car hikups under minor acceleration) It did the bucking when i let off the gas and everything, just like yours. I have a speed density 87. I took off the upper intake, cleaned it out real good along with the EGR valve. I also installed my 65mm T-body and spacer. I kept pulling a code 34. I still pull that code, but the problems are gone now. I think the code is there b/c i have a couple vaccum lines missing. I think the EGR was really crapped up and the engine was choking. Clean her out real good and see if thet helps. It did for me.
She still idles a little high but not that bad. Once again, i think that if from missing vaccum lines. Light Em Up!!
