Depends upon the car and engine. Most port and throttle body injection systems need fuel pressures between 35-50 psi. What is your reference to fuel pressure being weak? Before fuel injection became the norm, mechanical engine driven fuel pumps were in the 10 psi area. And before that, the fuel tank was mounted high and gravity fed fuel to the carburetor - there was no fuel pump. So, I say again, depends upon the car and engine.
That depends on the year, make, and model of vehicle. Not all fuel injection systems work at the same PSI/kPa level.
The pressure under which fuel is delivered to the injectors by the Fuel pump, governed by the pressure regulator.
How do you know it is? We don't because you did not even mention WHAT car it is!
manual fuel pumps 3 to 9 pounds for a cabrabtor.. fule injection ot tbi is 60 to 100 pounds of presser
Fuel pressure is weak
