1998 Dodge Dakota 3.9L V6 Magnum P0138: Fuel Cutout, Engine Bogging, and Evaporative System Issues

I'm experiencing persistent engine issues with my 1998 Dodge Dakota equipped with the 3.9L V6 Magnum engine. When idling, the vehicle runs smoothly, almost like a kitten—very smooth—but as I begin driving, the engine suddenly cuts out and boggs down. Once I floor it, the engine revs up and runs fine until it bogs again. I've noticed significant rusting in the Y-pipe of my exhaust system, which is leaking, and during a recent tune-up, I found gasoline residue in several spark plugs. I checked fuel pressure and it remains stable at 45 psi with the ignition on (accessory mode) and increases to 50 psi when running. The vehicle now displays a P013-8 diagnostic trouble code. Given that my exhaust Y-pipe is compromised, should I prioritize repairing or replacing this component before investigating the evaporative emissions sensor? What specific tests should I perform next to diagnose whether the issue stems from fuel delivery, sensor failure, or exhaust system leaks?