How to Test for a Sticking Fuel Injector

I ran into a problem with my Olds Silhouette van. It was running perfectly fine and the next day when I started it, it ran horrible. The idle was extremely rough and the engine warning light was flashing. I put my OBD-II tester on and it showed error code P0302 which means that cylinder number 2 is misfiring. I was running on 5 out of the 6 cylinders.

After troubleshooting that it was not an ignition problem, it left the fuel injection but how to test if it was a sticking fuel injector? There's two basic parts to a fuel injector: the electrical solenoid and the mechanical valve. A sticking fuel injector is a mechanical problem so it requires a mechanical test. The electrical solenoid is either going to work or not. You can measure its resistance with an ohm meter. Here's a short video on how to mechanically test if you have a sticking fuel injector

I tried it out just as the video states with the engine running. Three soft taps and the injector started working perfectly! The van is having all 6 injectors replaced as I write this. I figure it's like sparkplugs, if one goes then it's time to change them all. The other issue is that the GM 3.4L engine is a bitch to work on and if it is apart then I'm doing them all!

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Copyright May, 2011 Eugene Blanchard