01 Rio ???

OK so I have an 01 Rio. Check engine light is constantly on. Take it into the shop, and they hook it up. They say nothing is wrong and reset it. Comes back on immediately after leaving. Well, I think there really IS something wrong cuz the darn car shakes like it's going to fall apart when it gets up to 50mph. That and it sounds like a freaking rice burner with glass packs on it! Doe ANYONE have ANY ideas for me???? Thanks in advance

How many miles on engine?
WHen was last tune up?
How long since timing belt has been changed?
Is transmission working properly?

Go somewhere else and get the codes read and post them. Autozone does it for free