Information

1. Perform all diagnostic procedures for the incident per the applicable Service Manual.

NOTE:
For vehicles in states where alcohol is added to the fuel* (i.e., Arizona, Colorado, Illinois, Indiana, Minnesota, Nevada, Ohio, and Wisconsin), it is important to check injector resistance as follows:

^ Check each injector resistance, with the engine at operating temperature (not running), according to the applicable Service Manual procedure.

^ The injector resistance can be checked through the engine sub-harness to the injectors.

^ Under these conditions, the injector resistance must be between 10 - 19.9 ohms.

^ Do not perform injector cleaning if the resistance is not in this range.

* NOTE:
California is not included because MTBE (i.e., Methyl Tertiary Butyl Ether) is used in the gasoline. MTBE does not affect injector resistance, therefore California vehicles using MTBE gasoline do not need to have the injector resistance checked.

2. If after performing the Service Manual diagnostic procedures it is suspected that there may not be enough fuel flow through the injectors:

^ For vehicles that do not exhibit a continuous misfire, perform the fuel injector cleaning procedure provided in this bulletin.

^ For vehicles that exhibit a continuous misfire (dead cylinder), verify the injectors are operating (clicking open and closed).

A. If it is confirmed that the injectors are operating (clicking open and closed), perform the injector cleaning procedure in this bulletin.

B. If it is confirmed that the injectors are not operating (not clicking open and closed), determine if the electrical signal or injector is at fault. Injector cleaning cannot repair this situation.