What do the injectors run off? The computer? My gpas has a 88 ford f-150 and the two on one side won't work and neither will the one on the otherside..he's wondering what it could be?
Check to see if the injectors are getting power by using a 12 volt DC test light. They need a "trigger signal" to spray fuel. If they are, replace them. Given the age of Grandfather's truck I'd suggest replacing all of the injectors if the 3 that aren't working are getting power. HTH. -Jim
The trigger signal that Js was talking about comes from the ECM, you may have injector power but you will need to check for the trigger pulse, I would recommend getting a "noid light" for testing the injector pulse as they won't damage the injector driver in the ECM, and they plug right into the injector plug.