1993 Chevy Corvette Stall

My 1993 corvette began stalling (at all speeds) about 2 weeks ago. The engine will stall as if it is starving for fuel. Somtiimes after a short rest it would start right back up, and other times it required a "shot" of starting fluid in the throttle body intake and it would start right up. The fuel pressure was ranging from 37-43. I suspected it may be a fuel filter or fuel pump problem. I took it to a mechanic (because I just couldn't reach the fuel filter without the proper tools), and the fuel pump, fuel filter, fuel pump relay switch were all replaced, and the ECM checked out OK (no codes). However, the mechanic was dumbfounded as the problem continues. It does have an after market chip (Hypertech with a 160 degree thermostat), after market cold air intake that have been in for over 6 months and ran cool and like a Banshee on fire. But now it will stall and seemingly "shut down" the fuel/electrical aspect to the engine. Any ideas as to what the problem is