If you have to put the pedal to the floor to start the car you may have a Regulator problem. If you plug the manifold vacuum line that goes to the Fuel Pressure Regulator and the car starts and runs normally that may be the problem. If you have a problem starting you may also have a Fuel Pump Relay problem - turn the key on but not to start for 10-15 seconds and then off and then try to start in which case it may be the FPRegulator, at least that is my understanding.
Of course all of the above may not apply if you are not having starting problems at all. Also, the connecton to the PTU and the CAS can cause stalling problems. BAD GAS?