Originally Posted by frog

You say you changed the TPS, I assume you set it up properly, not just a case of fit and forget

I would check for leaks as said above (carb cleaner has been mentionned before ).

You may want to add dodgy wiring to your list, new sensors are no good if you've got a break in your loom, and we know they are getting old.
If it's a 4x4 sapph, worth cleaning the three connectors on the bulkhead with contact cleaner while you're there.

Good luck