Possible Causes & Corrections:

WARNING: This page does not describe the selected car, but rather 35 other vehicles, including the 1992 Pontiac Trans Sport, 1992 Oldsmobile Silhouette, 1992 Oldsmobile Bravada, 1992 GMC Yukon, and 1992 GMC Vandura Special. However, it is still accessible from the selected car via links, so may be relevant.

Check for obvious overheating problems.
Ensure initial timing is correct.
Check TPS adjustment and operation.
Check fuel system for low pressure or volume. Also check for induction air leaks.
Ensure ESC system is operating properly.
Ensure EGR valve is not always open.
Ensure TCC system is operating properly.
Remove carbon from engine with top engine cleaner.
If excessive carbon exists in combustion chamber, check for excessive oil burning due to leaking valve guide seals.
Check for incorrect basic engine parts such as camshaft, cylinder heads and pistons.
Ensure correct PROM is installed in vehicle. Check with dealer for latest application information.