Auto Parts: Vacuum, vacuum leaks, olds alero

Question
Hi. I have a 2001 Olds Alero that I spun off the road the other day. Right after that the "Service Engine Soon" light came on. The people at Auto Zone hooked up their hand held computer and told me that it had a vacuum leak somewhere. I'm not really familiar with the concept. Where is the vaccum? In the exhaust system? The fuel system? Is there any way I can diagnose this without having a mechanic hook it up to a machine?

Answer
Hi,
Pretty easy fix. Your engine creates vacuum when it is running, that is how it draws in the air that it mixes with the fuel that gets burned in the cylinders. If you are experiencing a vacuum leak, the engine is most likely running poorly also. Surging and erratic idle are typical signs vacuum is leaking. Another point to make is that the term 'vacuum leak' is misleading. When vacuum 'leaks' it is actually air leaking INTO the intake manifold so you won't physically 'see' anything. First place to look for a vacuum leak would be the MAP (Manifold Absolute Pressure)sensor which is a technical term for, you guessed it, vacuum. If this sensor seances a low-vacuum scenario it will trip the SES light indicating a problem.
Here's the disclaimer, there are ways to test where the vacuum leak is, I'm not sure I want to explain it to you being that you are not that familiar with auto technology. The procedure could potentially be dangerous. However, physically you could examine the intake manifold and related parts and see if you can find a disconnected rubber or plastic vacuum hose or maybe one that was broken. Take a close examination of your intake manifold area and follow every rubber and plastic line attached to it. If after a THOROUGH examination you still do not discover the open line, ask a follow-up and I'll try to explain the procedure for finding vacuum leaks with a running engine but like I said, the procedure could be dangerous if not performed properly and with care. examine with your eyes first, I'll almost bet that it is simply a disconnected vacuum hose or a broken one.
thanks for the question, I hope this helps. Ask a follow-up if you need more info.
Knucklebusters