GM Service Manual Online
For 1990-2009 cars only

Checks

Action

DEFINITION: A constant jerking that follows the engine speed, usually more pronounced as the engine load increases which is not normally felt above 1,500 RPM or 48 km/h (30 mph). The exhaust has a steady spitting sound at idle, low speed, or hard acceleration for the fuel starvation that can cause the engine to cut-out.

Preliminary Check

Refer to Symptoms - Engine Controls .

Engine Mechanical Checks

    • Perform a cylinder compression check. Proper compression is 2157 kPa (313 psi).
    • Inspect the engine for the following:
       - Improper valve timing
       - Bent pushrods
       - Worn rocker arms
       - Worn camshaft lobes
       - Broken or weak valve springs.
    • Inspect the intake and exhaust manifold passages for casting flash.

Fuel System Checks

    • Inspect the fuel system for a plugged fuel filter, a fuel system restriction, air in the fuel system, etc.
    • Inspect for water contamination in the fuel. Refer to Contamination Testing .
    • Inspect the fuel injectors for proper operation.