1990 buick regal idles great, die when press accelerator, has new fuel pump

A lot of new parts! Have a compression test done to gauge the engine's internal condition, and go from there. If compression is good on all 6 cylinders, scan for trouble codes. The compression test may find your problem, something like an exhaust valve burned or not seating properly.

This is probably an engine using a carburetor. If it starts and idles good and dies when the accelerator is pressed it is probably the accelerator pump on the carburetor. The accelerator pump supplies the fuel to operate the engine in this transition period from idle to part throttle until the venturi effect catches up to draw the necessary fuel the engine needs to continue running at the current demanded rate of speed. If the butterflies are opened and there is not sufficient fuel squirted into the engine when larger amounts of air are in demand it starves for fuel and thus stalls.If it is fuel injected then you have other problems, but my guess is it is a carburetor version. Ford went to fuel injection in 1990. You can just purchase the power valve if needed. You don't need the complete kit. Good luck

Is there a good vacuum supply to the MAP

Sounds to me like a fuel filter.When was the last time it was changed?Because if a car starts and runs till you give it gas under load then dies it is a fuel problem.Start by chaging fuel filter and if problem still persists then next thing to check is fuel pump.

Try a new distributor cap and rotor button,they are known problem areas.If the problem is not in the distributor then you will likely need to replace the catalytic converter,a plugged converter will not let the engine get to full horse power because it can't get rid of the fuel as fast as it is coming into the engine,which is not a problem for the engine at lower rpms but it is a problem when you need the power.

unfortunatly it sounds like you are having issues with the torque converter. it sounds like it is locking up all the time now. this requires the transmission to be taken out to change it i do not know what your experience is so not sure if you have the tools or knowledge to do it yourself.

check fuel pump fuse and fuel injector fuse.

gas pump

most likelly it is your fuel pump is not puting godd fuel pressure
have the fuel pressure test and if it is low have the fuel pump and filter replaced