Well, lets look at it again. He stated it stumbles on uneven track. When he shims that exact track, the engine runs fine. He checked for binding and didn't notice any. I'd have to say that something is causing the engine to stumble like crazy on uneven track.
So just maybe the power isn't flowing correctly to the board, or the board may have an issue?
I don't see it as you do John. I can't say you're wrong. I just know what I did to fix my Sunset engine that ran that way. It had some type of TMCC board set in it. I have to believe it didn't handle power fluxes, and motor control was poor at best. The engine was totally transformed with the PS2 board set so much that you'd swear it was a new engine. I have to believe that the PS2 battery back-up helped overcome any power loss issues for mine.
