Quoted from LTG:

Two things.
Balls magnetized and not rolling down the ball trough good. New balls. Unmagnetize them. Or this cures it too :
http://www.marcospecialties.com/control/keywordsearch;jsessionid=93543C0875FABC755D42D07BD60E21B1.jvm1?SEARCH_STRING=03-6809
The plunger that kicks the ball up and out to the shooter lane. It may be a tiny bit too high, and stopping the balls from rolling into position. The plunger/coil is mounted to a bracket that is secured to the end of the ball trough. Four screws on the end can be loosened and the whole coil bracket can move up or down. Just a tiny bit. Too much or too little and it won't kick good.
LTG : )

Quoted from LTG:

Two things.
Balls magnetized and not rolling down the ball trough good. New balls. Unmagnetize them. Or this cures it too :
http://www.marcospecialties.com/control/keywordsearch;jsessionid=93543C0875FABC755D42D07BD60E21B1.jvm1?SEARCH_STRING=03-6809
The plunger that kicks the ball up and out to the shooter lane. It may be a tiny bit too high, and stopping the balls from rolling into position. The plunger/coil is mounted to a bracket that is secured to the end of the ball trough. Four screws on the end can be loosened and the whole coil bracket can move up or down. Just a tiny bit. Too much or too little and it won't kick good.
LTG : )

Quoted from pinballinreno:

It's probably just a little bent. Raise it grab a hold of it bend it back towards the back glass a tiny bit be careful don't cut yourself on the metal flap.

Quoted from LTG:

Two things I'd check. The troll carriage has the top metal box and a collar pressed into it. If that joint comes apart can cause binding.
The other thing to check is the long plunger inside the coil that pushes the troll carriage up. It is two pieces, held together by a roll pin. If that roll pin creeps out, it will drag on the inside of the coil sleeve. Also see if the coil sleeve is cracked or broken.
LTG : )