Possible Cause & Correction

Check EGR operation for being open at all times. See EGR SYSTEM CHECK chart in the TBI TESTS/CODES article in this section.
Check output voltage of ignition coil.
Check for crossfire between spark plugs (distributor cap, plug wires, and proper routing of plug wires).
Check for intermittent condition in primary ignition system.
Check ignition timing.
Check for faulty spark plugs, plug wires and/or plug boots.
Check for proper valve timing.
Check engine compression (leaking or sticking valves).