2004 audi

#1

I USE 89 GAS AND MY CAR IS SHAKING WHAT CANT I DO?

#2

Try a tank of 93 gas.

#3

It’s going to be impossible for anyone to even make a wild guess based on the near total lack of information given about the car and the problemn.

For starters, how about:
Mileage on car.
Shakes at idle, at speed, or both.
Any Check Engine Light on.
If the CEL is on is it flashing.
When, if ever, were things such as spark plugs, fuel filters changed.

Answers to those might get the ball rolling.