DTC 88 - TDC Offset Error
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 1994 GMC Yukon, 1994 GMC Suburban, 1994 GMC Pickup, 1994 GMC Cab & Chassis, and 1994 GMC C3500 HD. However, it is still accessible from the selected car via links, so may be relevant.
This DTC indicates there is a pump timing problem. This DTC will set if TDC offset is greater than plus or minus 2 degrees, or the PCM has lost memory (TDC offset is stored in PCM memory). Check injection pump timing. If okay, program TDC OFFSET into PCM. When all diagnosis and repairs are complete, clear DTC's and verify operation.