Vacuum leak ,egr not seating, bad tps,  low fuel pressure.lots of
possibilities.

<lb5565@earthlink.net> wrote in news:pHfWf.11101$k75.1860
@newsread3.news.atl.earthlink.net:

back yonder in them days GM had a prob with Mass Airflow Sensors in the 2.8
genre. rarely did it set a code..........instead of making a MAF sensor
that would hold up they installed new software (chip) in the ECM that did
away with MAF input and went to a speed density system...the MAF sensor was
left intact because it fed the processor the IAT input also........if the
alteration was done it should have a sticker on the radiator support,
upper, indicating the repair (?).............if not, i would beg, borrow,
or steal a known good MAF sensor for a try if no codes are
present..........from a fuzzy memory, kjun.................

If the battery was recently unhooked, then the computer will need to relearn
how to idle the engine properly. While it is learning the engine will idle
poorly.

If you don't have a MAF sensor it may help to spray some intake cleaner in
the throttle with the engine running. It won't hurt, they usually need a
good cleaning after a while.

Vacuum leak is a likely cause though. You'll just love all the places they
were put on your engine.