 System Too Lean , Vacuum and idle issues
This is not for those with a vacuum leak. This is for those with no vacuum leak no maf problem no egr system issue. Ford built a few vehicles with a vacuum line that goes to the brake booster that is also teed with a line that goes to the intake tube in front of the throttle body. Vacuun must dead end to create vacuum. With a constant source of air as is supplied by the line going to the intake tube the iac and maf never get a good reading and cause idle issues performance issues as well as the system too lean code.Ford swears they never designed a system like this but I have seen it more than once. If you remove the line between the tee and the intake tube your problem will go away. ( be sure to cap the now unused ports!) Vehicles that I have seen this in include Explorers, Contours, Mystiques, Escorts and ZX2. | 
