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I have an 03 F-350 with PSD with MBRP 4in turbo back exhaust, S&B intake, and Edge Juice w/ attitude. I replaced my muffler with a delete pipe about a week ago and soon as I started her up got a check engine light. Maybe a coincidence but when I pulled the code it was P0401, EGR flow insufficient. My MPG's have also tanked in the last week. Thinking the EGR might have something to do with that. I was thinking I would just disconnect the EGR and clear the code. Can any one tell me if the two are related or is it just weird timing.
It is just coincidence, many people run staight pipe without any problems.
The P0401 Code is specifically a sticking EGR valve by definition.
P0401: "Exhaust Gas Recirculation Flow Insufficient Detected; EGR Valve Position does not match desired, limits based on engine speed / load.
EGR Valve stuck or sticking - EGR Valve Position Sensor Bias - EP Sensor bias."
Also with the latest flash the EP sensor is turned off and no longer used.
Sounds like you need to clean or replace the EGR valve.