Most mechanics will tell you it could be anything, and a lot will rule out a computer problem till you have fixed every other possible option. I'd say if you know someone with the same car as you, even just another GM 2.8 would do, try switching the computer to see what happens. It only takes 5 minutes to try it, 3 10mm nuts on the thing in the dash. Might want to take the cover off and put your module in the other computer if not the same car. When mine was stutterint, I put in a computer from a Pontiac 6000, it worked good, but the guages were wrong till I put my chip in the other computer.
Try it if you can, but don't spend big bucks to get a new one right away or anything.
Try it if you can, but don't spend big bucks to get a new one right away or anything.