Hmm, I might think timing too, if you just had a tuneup, but Twizted sounds right too. How'd it run immediately after the tune-up? Is the idle lower than normal? Maybe they left the hold-down a hair too loose? Were the plugs/wires/cap/rotor replaced in the tune-up? One other thing you might look at; I had a 2.8 with MPFI, and there's a thing that screws in right behind the throttle body, I'm totally strapped for what it's called right now. Twizted will probably know. It's large, maybe a 7/8-13/16, and has a 4-prong connector in the top. Whenever I did a tune-up, I cleaned that out good. Cripes it was so long ago, I can't remember what I cleaned it with, injector cleaner or carb cleaner. Heck, you may not even have one on TPI, been a long time for me...
BTW, FYI, I had two pumps fail in my Camaro within a couple years of each other, both AC Delco (first was the original, though). They may be the same pump for MPFI and TPI... Can you get into the diag connector with a manual? I remember there being a fuel pump test lead. Maybe you can run the pump without the engine for a while with a guage on the fuel rail, see if it's putting out consistent pressure. If it's not at the diag connector, the fuel pump/sender wires have a plug/connector at the body, directly above the diff pumpkin, right behind the rear seats. Before I did mine the second time, I tested it through that connection. I couldn't tell you the colors, it's been too long a day... I think blue with white stripe is the pump... Avoid lotsa sparks, though...
I ought to keep my mouth shut, I'm not all that together right now. But I hope I said something that helps!
Ratch
**Hmmm. Land or Mall? Land or Mall? Let's see. Lotsa SUV's around here... Let's build a mall.**
