I've never seen a bad TPS kill spark either, but it should be replaced if it's bad to rule out that possibility.

the adjustment nut is on the front cover, 14mm.

Thanks, just picked up the angle sensor and haven't installed yet. Can't seem to find the clutch adjustment nut. Going to check out link you posted  Thanks

Sounds like a low battery, out of adjustment clutch, or shift motor going south.   Don't put that new angle sensor on it yet.    First thing you need to do is the battery.  Clean connections and top the battery off.   Then try adjusting the clutch.  Nut on the front cover.  Loosen it, then turn the screw in the middle counter-closckwise till you feel resistance, then back to the right 1/4 turn and lock the nut back down.   If the adjustment screw doesn't turn easily, it might be seized.  Don't force it, just leave it for now and come back to it.   Here's Retro's ES thread.   Your shift motor might be going south, or it could just be gunk in the gears under the shift motor.   If you do replace the motor, OEM only, even if you buy used.  No aftermarket crap.    

No blinking lights, shows "N" but just "clicks" at transmission as it tries to shift into gear. If I slowly roll the machine and shift it will pop into gear with engine off or running.   Steve