Not to try and hijack this thread but since it seems I have the same problem, maybe I can be of help. I plugged my ODB2 reader into it (mine is a 98) and saw that the jerks/buck I was getting ROUGHLY corresponded with a drop in the MAP data (not always tho, sometimes it would jerk, but nothing...
Any updates on this? I seem to have the exact same problem, except I didn't change anything yet, just checked the TPS voltage and the CPS resistance. I will try the brake light switch this weekend