Thanks for all the replies.
Tonight I flipped the engine over and applied power to the center roller and the outside wheels and had the same problems. If I moved the outside wheel lead to the post where the tender attaches there were no problems at all.
Seemed like the copper connector that bridges the front 2 wheel sets has some intermittent connection issues. I removed it and rebent the connect for better connection, still has some "pulsing" of the headlight but at least the train ran. Can I apply something like dielectric grease on the copper/wheel connection? Just looking to make the electrical connection a little better.