1995 Chevy Blazer Its idle is to high

Shakes or Wobbles problem
1995 Chevy Blazer Engine Size unknown Wheel Drive Type unknown Automatic 000000 miles

I'm interested in buying a vehicle but before I do if there is a problem with it I'm infamiliar with I'm going to come on here and ask so I know before I make any other buying mistakes. This Blazer has an oil leak which is one thing but the girl says that it won't pass smog because the idle is to high and thats why it also shakes at a certain speed. Can you please confirm this as soon as possible thank you.