Diagnostic Aids

WARNING: This page is about a different car, the 2003 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

Monitoring the misfire current counters, or misfire graph, may help isolate the fuel injector that is causing the condition.
Operating the vehicle over a wide temperature range may help isolate the fuel injector that is causing the condition.
Perform the fuel injector coil test within the conditions of the customers concern. A fuel injector condition may only be apparent at a certain temperature, or under certain conditions.