I've never seen the TPS stick not sure what is causing that. Guess you'll need to figure out if it is mechanically sticking open or if it is an electrical failure. My hunch would be electrical failure but could be either. You can replace the TPS but you would need to order one or call Holley and ask for a warranty replacement.

Voltage needs to be in the normal range for the Sniper to work so you'll need to figure that out for sure.

Did you run some data logs while you were taking the test drive? You should always data log your test drives so you can play them back and see what happened. Data logging is the basis for problem solving with a Sniper so if you aren't using the data logger then you're taking the hard road.