ARMY TM 9-2815-257-24 AIR FORCE TO 38G1-128-2 MARINE CORPS TM 10155A/2815-24/3 3-11 Table 3-2.  Unit Level Troubleshooting (continued) MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION 4. ENGINE OUTPUT DROPS a.    Check for clogged or dirty air cleaner. Remove and replace air cleaner element (Para. 3-16). b.    Check for improper valve / rocker arm clearance. Adjust valve clearance (Para. 3-15). c.    Check for clogged, sticking, or worn fuel injector nozzle. Remove and replace fuel injector (Para. 3-14). 5. ENGINE RUNS ROUGH a.    Check for clogged, sticking, or worn fuel injector nozzle. Remove and replace fuel injector (Para. 3-14). b. Refer trouble to direct support maintenance level. 6. LOW COMPRESSION PRESSURE a.    Check for improper valve / rocker arm clearance. Adjust valve clearance (Para. 3-15). b. Check for leaks around fuel injector. Tighten injector nuts to 7 to 9 ft-lbs. (100 to 120 kg-cm) (Para. 3-14).    c. Refer trouble to direct support maintenance level. 7. ENGINE EMITS WHITE SMOKE a. Check to see if engine oil level is too high.  Check for contaminants in the oil system Drain and service engine oil (Para. 3-5). b. Check for improper valve / rocker arm clearance. Adjust valve clearance (Para. 3-15). c. Refer trouble to direct support maintenance level.