Quickly diagnose "no start" and engine miss conditions in the electrical fuel injection and spark plug circuits. Analyze rough running engines. Contains a noid light set to test electronic fuel injection signals and a in-line ignition spark checker shows a duplicate view of ignition spark. Supplied with instructions in a durable, plastic molded storage case. Noid light are supplied to check: Bosch PFI, Ford TBI, Geo TBI, GM PFI, GM SCPI, GM TBI