Michael Bacon

I was driving back home when all the sudden my cars exhaust got louder, poor gas milage, slow acceleration, and won't pick up speed after 3g feels like its clogged or something. When I shift it sounds like there is a release valve from a turbo. A rush of air when shifting. Changed the oil, tps, what could be going on with my car?

Jiyu

If it's an old, high-mileage car, the catalytic converter could be clogged. Put your hand at the exhaust pipe and have someone rev the engine. Compare how it feels and sounds with a similar car that's running well. If your state doesn't require emissions inspection for registration, you can just remove the cat from the exhaust.
Muffler may also have rusted through. Crawl around underneath and see what the ex. system looks like.
Maybe replace the fuel filter. If it's clogged, the engine won't be getting enough fuel.

Do a proper tune-up. Pull plugs and see what they look like. The plugs will tell you what's going on inside the cylinders, maybe replace them. Replace air cleaner if it's old. Clean mass airflow sensor (easy to to do, YT videos).

Buy a cheap scan tool, plug it in and see what the codes are. Or, go to an auto parts store that will scan it for free, then look up the codes online.