hot start stall?

[suburbanguy]

Hi, I'm new on here, bought a 94 suburban in February. It has never had a whole lot of power and only gets like 9-10 mpg. Lately, though, it has started to stall right at start up when the engine is warm (20-30mins after stopping when running to the store or something). My wife thought it might be the tps (throttle position sensor) so we were gonna test it and she unplugged it. Then we decided to just buy so she put it all back together (air cleaner and all) to meet me at the store and miraculously, the truck ran fantastic, loads of power, and stuff. Then yesterday, it stalled on her 4 times and today the power was gone... Could the tps be bad and we just got lucky or is it something else? Help!