1991 Cadillac Deville Acceleration problem.

1991 Cadillac Deville V8 Automatic 133000 miles

I was driving my car on my way home, the car just suddenly slowed down. I pressed on the gas to give it more power but it's not accelerating the way it normally does. I put it on park and it's still not accelerating. The car sounds different now like it's choking sounds, sounds rough. I had a turn up done yesterday but it's still not accelerating. Does anyone know what the problem is? Or do you have any suggestions? THANX! Jayla