The check engine light is on.

I can hear a click, much like an arcing ignition wire.

I can feel a click by holding the wires leading to the 4th fuel injector.

The manual says I should check resistance at the injector.

Based on experience, does it seem like I need an injector?
Are the 940gle (double overhead cam) injectors interchangeable with 240 or 740 injectors?
Do I have to remove the entire fuel rail to replace one injector?

Thanks,
- CarlD trimagna@yahoo.com

I measured resistance on the 4th, possibly defective, injector and a good injector. Both measure about 16ohms.

Removing the wire from the 4th injector definitely slows the engine, so it must be providing some fuel.

I removed the 4th spark plug. It was in a well filled with about 2 inches of oil.

The click remains and the check engine light is still on.

Hopefully, the pool of oil is due to a bad valve cover gasket. I will try to replace or tighten the valve cover, but that doesn't explain the click.

I am homing in on a more serious problem like a valve or cracked piston ring.

You can pull the injector off the rail: no need to pull the rail. Use new o-rings when reinstalling.