getting 90 PSI at fuel rail - help

skidad

Member
Sep 30, 2026
28
8
13
Ohio
2001 Mustang GT 2v and everything is stock. So I've been fighting high fuel pressure when the engine is shut off - my gauge shows 40 when i first shut the engine off and rises all the way to 90. The mustang is new to us this summer and runs perfect otherwise. I replaced the fuel pump this week with a Delphi FG0827 thinking maybe the check valve was sticking or something was failing in the pump assembly. I didn't know till i pulled the tank but it had the same Delphi pump in there with 2024 date code but I already had the new pump.

New fuel pump didn't fix my issue. Are there any other components that could cause the fuel pressure to rise like this?

BTW, my analog gauge matches my scanner with KOEO. Been fighting this issue for the last few months and not sure what to do.
 

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