Lack of Power/Sluggish/Spongy/Stumble

1. Air filter dirty or plugged
2. Improper ignition timing.
3. Fuel filter restricted.
4. Contaminated fuel.
6. Improper EGR valve operation. See chart C-7
7. Improper alternator output voltage.
8. Improper valve timing.
9. Improper compression.
10. Worn camshaft.
11. Improper secondary ignition voltage.
12. Restricted exhaust.