Engine troubles are not usually caused by the EFI system. When troubleshooting, always check first the condition of all other related systems.
Many times the most frequent cause of problems is a bad contact in a wiring connector, so always make sure that the connections are secure. When inspecting the connector, pay particular attention to the following:
- Check to see that the terminals are not bent.
- Check to see that the connector is pushed in all the way and locked.
- Check that there is no change in signal when the connector is tapped or wiggled.
Actual troubleshooting of the EFI system and the EFI computer is a complex process which requires the use of a few expensive and hard to find tools. Other than checking the operation of the main components individually, we suggest that you leave any further troubleshooting to an authorized service facility.
The worst enemy of any fuel injection system is water or moisture. The best (i.e., cheapest and simplest) insurance for your truck's injection system is to change the fuel filter as frequently as the maintenance schedule recommends. When you follow the filter change interval strictly, many possible expensive injection system problems are eliminated.