How do you find vacuum leak on a 91 pontiac grand am?

How much would it cost for a mechanic shop to use smoker to find vacuum leak?

• I suspect I have a vacuum leak somewhere around the throttle body or the intake manifold. I already changed the intake manifold gasket and while the old one was pretty deformed and corroded, it made no difference after installing the new one. I hate wasting time and money changing parts that I don't have to. I know some mechanic shops use a smoker that you can see where exactly the leak is coming from. They are really expensive so it's not practical for your average joe to buy for one project. So does anyone know how much it would cost for a shop to just find a leak with these smokers? If it's under 100 I would happily pay just to avoid the trouble of changing a million tubes and parts only to find out it's not even a leak and it was just some sensor. I googled some stuff but have yet to find an estimate for this kind of test. Just wondering if any mechanics here can give me an estimate.

• Answer:

  You don't really need a smoke test. Just start the engine and squirt WD40 in the areas of suspected leaks. You will be able to see and hear when the suction is temporarily created by the WD40 being sucked into the leak.