Welp.. replaced the throttle position sensor and it's still been stalling out, losing power, and dropping RPM. I got a fuel pressure gauge on it and have been driving around with it and recorded the following video:



This is just slowing down from foot on the gas to a stop. Looks like it's fluctuating about 10 PSI. I haven't had it stall out/lose power on me yet when I've had it hooked up to the pressure tester, but will update if I can get it to happen.

Does anyone have any idea if this is an acceptable PSI fluctuation, or does this alone point to the fuel pump/system as the culprit?