The problem is a vacuum leak. If the system works when the engine is at an idle and not under a load, chances are you have a leak under the dash. Check for leaks there first, and see if you can locate the supply hose from the engine to make sure it is working. If they are all attached, make sure there are no unrelated vacuum leaks on the engine which could lower the pressure.
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Sunday, June 30th, 2013 AT 9:30 PM