Vacuum leak on 2003 Ford Explorer

I have a 2003 explorer with 139k. I have replaced the plugs, wires, coil, fuel filter, and the #6 injector. The truck still idles rough and it sounds like it has a vacuum leak. All the lines on the top of the motor are tight. Are there any below that I am missing?

by in Eads, TN on May 23, 2011
1 answer
ANSWER by on May 23, 2011
Pinch off all vacuum hoses with a pliers. If any changes occurs, it could be a leak. One particular area that is comon for these vehicle is the intake manifold gaskets. A propane method is a sure way of detection, but monitoring the O2 sensors is desired when doing so. The manifold gaskets usually are more prone to leak during cold starts.
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