Fuel Injection System
Before suspecting fuel injection system as source of engine trouble, other engine systems should be checked. Ensure that air intake and exhaust systems are not restricted, and that fuel supply system provides an adequate amount of clean fuel to injection pump. If a problem still exists after checking these systems:
- Check fuel lines to injectors for kinks or restrictions. Replace as necessary. Run engine at RPM where problem was most pronounced.
- Momentarily loosen fuel line, 1/2 to 1 turn, on one injector. Then tighten fuel line. Repeat for each cylinder.
- If there is no difference in engine operation when a fuel line is loosened, that injector should be removed and tested.