Need serious help!! 1999 Audi A4 Quattro 2.8.

I have an 1999 Audi A4 Quattro 2.8 base model. So the issue is it just it wont go past 1000rpm it just sounds like it wants to die if i hold the gas down and if i let it idle it dies. Many different people have told me different things that could be the problem. I've changed the MAF sensor, Fuel pressure regulator and broke out the catalytic converters in case there were clogged and still nothing. It drives but it feels like something is holding it back it only goes up to 30mph max and it has trouble getting to 30mph. It just happened out of nowhere one day I got in my car to go home after work and thats when it started. Took me like 15min to get home when it normally takes me 5min, it felt like it wanted to die and it would accelerate pass 30mph. I would appreciate more ideas on what the problem might be. PLease!!!!