1998 Ford Contour 4 cyl Front Wheel Drive Automatic 168000 miles
the check engine light has come on, I have taken my vehicle to my mechanic and the 'computer reader' told us that I have a vacuum leak. What is the most likely place that the leak is? Also, when I am idling or in neutral or park sometimes the engine revs up and down, and there is a whistle when the engine revs up.
Yeah that is a vacuum leak, look behind the engine by the firewall. Look at the pcv valve and see if it is disconnected or cracked. If that is not it, get yourself some throttlebody cleaner or brake kleen and mist it around all the hoses while the engine is running, when the idle changes, that is where your leak is, or take hold of the throttle linkage and rev it up a little till you get the whistle noise to see if you can detect where it is.