This is one of those completely weird problems that you'll need to do some pretty exact troubleshooting and observation to fix.

Switch test and coil test are your friends!

In switch edges test, activate the shooter switch with the ball.

Then activate the Gear lever switch.

Look very carefully and see if the switches are working perfectly, AND that they do not activate anything but the switch they are assigned to. We are looking for two switches activating, or a whole row/column.

Then do the same kind of thing in the coil test. Check to see that the correct coil (up ramp, plunge kicker) is activating, and only the correct coil.

Do a careful inspection with the playfield raised and check for a terminal or wiring on the coils that might be pinched together, or touching something inappropriately.

Also check the wiring to the switches.

I'd particularly check the plunger coil, and look carefully to make sure the terminals aren't touching anything they shouldn't be when the playfield is in the closed position.

The gear lever can have pinched wires that only connect inappropriately when they are flexed in a particular way, so in switch test try your hardest to get the switch to fail by moving the gear lever to every position, tug on the wires (a little), try to force a failure.

This problem sounds like something touching that shouldn't, or a couple of things touching that shouldn't!

Let us know what you find!

Well, that's... interesting.

(You never want your service guy to say that...) Hehe.

Seriously, that's good news, you've eliminated that as a problem.

Let us know about the switch and coil test results. I suspect that you will find the switches and coils work perfectly instead of something obvious, but when you've got a really unusual problem the best troubleshooting advice is to check all the simple stuff and make sure that you've got an exact understanding of what is and isn't working.

Let us know!