The symptoms you have are classic low
fuel pressure, check the filter, and the
fuel PSI, both at idle and trying to drive,
see what happens, My vote is for the
Regulator, fuel PSI should be around
36-43, 36 is correct for TBI systems, I'm
not sure if the MPI system is higher or same.
A quick regulator test is to pinch shut the
return line and see if it runs better, might
not need to pinch all the way as it might
cause it to stall instead of idle.
Wild