Poor engine performance

My daughter has a 1993 3.3 grand am. Engine stslls on cold start, will restart fine, may idel ok or stall when put into gear. lacks power from stand still, performes fine at crusing speeds, shifts fine in and out of gears, performes a little better when hot. replaced fuel pump, fuel filter, sparks, wires are fine, air filter, No SES light. HELP!!!

This engine uses a fuel pressure regulator. It needs to be checked out because a malfunctioning regulator can starve the fuel injectors. A good mechanic can check the required pressure at the regulator to see if it’s within limits (30-40 psi). The mechanic can also check for a kinked/bent fuel line to the regulator as well.

I did that 40psi on the button. No kinked or bent fuel ines.

Check for cracked vacuum lines.