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Does the FRP read the same and the fuel pressure still at 90 PSI after the FRP and pump were replaced or before?
Actual fuel pressure tested with a manual fuel pressure gauge should be reading the same as the FRP while the engine is either running or the key is turned on. The PCM uses the FRP to monitor the fuel pressure and then regulates the power to the fuel pump to control the fuel pressure through the fuel pump driver module.
Let me do a little digging, I'll be right back.
Do you have a scan tool that can monitor the Long fuel trims and short fuel trims?
Actually, monitor the trims and then disconnect the line from the vapor management valve to the intake and plug it off to stop any vacuum leaks and see if the short fuel trims return to around 0.
What were the short fuel trims?The long are the learned/adjusted.
The short are actual at that moment.