TM10-3930-660-20 Table 2-3. Mechanical Troubleshooting (Cont’d) MALFUNCTION TEST OR INSPECTION CORRECTIVE  ACTION Step 4. Step 5. 4. ENGINE Step 1. Step 2. 5. ENGINE Step 1. b. Service air cleaner elements, TM10-3930-66O-10. Check for air in the fuel system or inadequate fuel supply. Bleed the fuel system, para. 5-12, or fill fuel tank as necessary, TM10-3930-660-10. Check for contaminated fuel. Obtain sample (see TM10-3930-660-10). Verify by operating the engine with clean fuel from a temporary supply tank. Drain and flush the fuel supply  tank. SURGES (speed change) If surging occurs at idle, check if idle speed is set too low for  accessories. Adjust idle speed by adjusting accelerator cable as necessary, para.  5-21. Check for high pressure fuel leak. Replace high pressure lines, or tighten fittings, injector sealing washers or delivery valves, para. 5-12. STARTS  BUT WILL NOT KEEP RUNNING Check for idle speed too low for accessories. Adjust idle speed by adjusting accelerator cable as necessary, para.  5-21. 2-28