Long story: when car moves from stand still sometime it bogs.sometime on full throttle it feels like it is lagging fuel.won't pick up speed

If car is off for approximately hour, I have to wait some seconds so that fuel pressure gets and it starts with half self. I can hear fuel pump when I turn the switch on it goes like eeeeeeeee and after fw seconds uuunnnnnnnn. When the sound changes then it start instantly

My fuel pump is powered by external relay. The voltages when switch is turned on is 11.6 volts and after dew seconds it drops to 9v.

I do not have fuel pressure gauge but I tested by blocking the fuel pipe with thumb.it takes some force to block fuel but I can stop it with switch on.

I suspect
fuel pump voltage regulator for waiting to fill pressure
Distributor rotor and cap for sputtering at low rpm