My sons chevette idols fast. When he first tries to start it most of the time it won't start just turning the key, you have to mash the gas several times then start it. When the car comes to a stop it stops running and you have to mash the gas several times to start it. Just had tune up a new valve cover (?) put on. It also burns a lot of gas which suprises me since it is a compact car and should be great on gas. Can you help me?

Sounds like you need to clean and "rebuild" the carburetor. Normally, on that car you would press the accelerator to the floor several times, to pump raw gas into the carburetor and to set the automatic choke. If you need to do more than that, then the carburetor needs rebuilding.