Unstable Idle

1. Incorrect idle speed, on A/C models check fast idle device operation.
a. Reset to specified range.
2. Check accelerator cable for binding or twisting, check accelerator lever for looseness.
a. Repair as necessary.
3. Check for water or air in fuel filter/water separator.
a. Drain water if necessary.
b. Prime system using fuel filter hand pump, find air source and repair.
4. Injection timing.
a. Check injection pump alignment mark to block mark, adjust as necessary.
5. Check engine mounts for loosening or cracks.
a. Tighten or replace as necessary.
6. Faulty injection nozzles.
a. Repair or replace as necessary.
7. Low compression.
a. Check compression, repair as necessary.
8. Excessive valve clearance.
a. Adjust valves.
9. Valve train trouble.
a. Check timing belt and camshaft installation, repair as necessary.
10. Injection pump faulty.
a. Overhaul or readjust setting of injection pump.