GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2000 🢒 Savana 🢒 Engine 🢒 Engine Controls - 6.5L (L65) 🢒 Cuts Out, Misses

Checks

Action

DEFINITION: A steady jerking that follows the engine speed, usually more pronounced as the engine load increases. The vibration is not normally felt above 1500 RPM or 48 km/h (30 mph). The exhaust has a steady spitting sound during idle, low speed, or hard acceleration due to the fuel starvation that can cause the engine to cut-out.

Preliminary Check

Refer to Symptoms .

Ignition System Checks

Check for a cylinder misfire:

  1. Start the engine.
  2. Allow the engine to stabilize.
  3. Perform the injector balance test.
  4. If there is no RPM drop on one or more of the cylinders, or if there is an excessive variation in drop, refer to Engine Mechanical Checks in this section.

Engine Mechanical Checks
    • Perform a cylinder compression check. Refer to Engine Compression Test in Engine Mechanical.
    • Check the engine for the following conditions:
       - Improper valve timing
       - Bent pushrods
       - Worn rocker arms
       - Worn camshaft lobes
       - Broken or weak valve springs
    • Check the intake and exhaust manifold passages for a casting flash. Refer to Intake Manifold Cleaning and Inspection and to Exhaust Manifold Cleaning and Inspection in Engine Mechanical.

Fuel System Checks
    • Check the fuel system for a plugged fuel filter, low fuel pressure, etc. Refer to Fuel Supply System Check .
    • Check for water contamination in the fuel.

Additional Check
    • Check for electromagnetic interference (EMI)--The EMI on the reference circuit can cause a missing condition.
    • Monitoring the engine RPM with a scan tool can detect an EMI.
    • A sudden increase in the RPM with little change in the actual engine RPM will indicate that an EMI is present.