Possible Causes & Corrections

Check the following items:

• Ensure EGR valve is not stuck open.
• Check engine for sticking or leaking valves.
• Check for proper valve timing.
• Check for engine vacuum leaks. Ensure engine is tuned to specifications.
• Using Spark Tester (J-26792), check available output voltage of ignition coil.
• Check for crossfire between spark plugs, distributor cap and spark plug wires.
• Check for intermittent ignition system problem.
• Check for erratic spark timing or reference (RPM) signal.
• Ensure initial ignition timing is properly set.
• Check for fuel or water in vacuum hose to MAP sensor. Also check for restricted hose.