Problems after Fuel Filter Replacement

[Joncho]

Hi, I'd like to pick your brains a little bit here because I have no idea what it could be..

I replaced my fuel filter a while ago hoping it would fix my slow crank problem (Ended up being the Fuel pressure regulator. Wanted to try the cheapest option first though).
Since then I have loss of power while accelerating quickly. Sputters / kicks sometimes too. Occasionally on hotter days it will stall if I've come from highspeed to a stop, like a red light after coming off the highway.

This happened after replacing my fuel filter, so I put my old one back. But I still have these issues. What could I have bumped / done while in the process of changing it that would lead to this? Or is the timing just coincidence? One guy I talked to at the dealership told me that old fuel pumps will show problems after relieving the line pressure.
It's worth noting that there is a distinct plastic / electric sort of smell coming from the gas cap region after driving for a while.
I also have P0172 Generic System Too Rich and P0107 Manifold Absolute Pressure/BARO Sensor Low Input codes. But one or both of these were pre existing.

Any thoughts or insight would be greatly appreciated.

[alschnertz]

Coils & wires.