the plenum (right under the driver's intake hose-throttle body and above the other hose underneath-intercooler hose I think). The end going into the plenum was "sabotagge'". That hesitation problem is quite annoying though. This past few days I have driven the car like a mad dog. Lots of racing and top end runs during the tuning process. Guess how many miles I got in a full tank of 92 octane gas....160 miles....Do you think leaky injector/s could cause poor gas milage and hesitation?