Holley Sniper EFI
I've solved the issues I've had recently. I gave the motor a wash and apparently it's a bad idea to get any moisture near the TPS. From the symptoms presented - TPS not zeroing and an eratic/non responsive IAC - I replaced both and now its settled. I narrowed it down to the TPS getting moisture in it. Apparently its a common problem so I thought I would post it up.