EGR (Exhaust Gas Recirculation) If you disconnect and remove it, your check engine light will come on and stay on. You won't notice any difference in MPG. You really shouldn't bypass it because many states require emission inspections, and it is part of the emission control system.
If you do live in a state where that isn't a concern, A company like www.tbichips.com can custom make a chip for your truck - with the EGR option disabled.
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