Q: Q: Fuel pressure

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My first check I was told my 02 sensors where too lean I replaced all 4 of those no change the cat on my right side rear turned red sent to shop to replace not clogged and or bad replaced almost all sensors pcv mas air flow throttle body and all problem still sent to dealership for a deeper check to find out my fuel pump is putting out 9 psi and my truck needs 45psi could it be the pressure sensor on the full pump that is bad and not the sending unit had checked at first shop i was told I'm getting gas I have a 5.4v8 Triton 4wd

My car has 185000 miles.
My car has an automatic transmission.

There are a number of things that may cause low fuel pressure such as a weak fuel pump, clogged fuel lines, clogged fuel filter or a bad fuel pressure regulator. This can happen when the pump itself is not working properly or when the fuel pressure regulator is not maintaining the proper fuel pressure in the fuel system causing the engine to starve for fuel. This can also happen when there is insufficient connectivity to the fuel injectors which can cause an intermittent fuel spray pattern into the intake system resulting in a lean fuel condition or the motor otherwise starving for fuel. I would recommend having an expert from YourMechanic come to your location to diagnose your fuel system.

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