What can I do to check the power going to a fuel injector? (Don't say lick the contacts while it's running!)

I've seen write-ups that mention an oscilliscope, but was hoping there was some easier / less expensive method.

Was gettting a P0303 code, so cleaned all injectors and put #3 on Cylinder 7. It hasn't thrown a code yet, but the vibration / miss is still there and when I pull the connector on #3, I notice no change in idle. But when I pull others (and #7 which was the former #3) I do notice a change in Idle.

Thanks,
Lee

 

If there is no change at idle when you unplug the injector there's a chance the injector could be plugged.

 

My manual says you should be able to get a special injector harness test light (noid light) from most auto parts stores to check if your getting anything at each injector connector.