I have an 02 Chevy Silverado which is showing code of PO171, PO174, PO300.?

[Billy]

Fuel pressure is at 48 psi. When the fuel pressure regulator line is disconnected - the pressure is 58. I have the regulator disconnected and vacuum line plugged right now and the engine still lopes both when the engine is cold and warm and sometimes will stall out at traffic lights. I have recently replaced the fuel filter, pressure regulator and fuel pump was replaced approx 2 months ago by the dealer who sold me the vehicle - and was told it IS a Delco fuel pump. I have also replaced the mass air flow sensor - although that was replacedwith an after market brand.
Hope that someone can offer some insight as to why the truck continues to have the above codes.
Thanks
Billy

 

[Mark F]

You are doing everthing but addressing the real problem. Take it to a shop to have it properly diagnosed. What you are doing now is wasting money on parts you don't need and possibly damaging the motor.

 

[Bob M]

po171 and 174 are oxygen sensor codes the po300 is a misfire code