I have a 2007 Aspen 4.7 flex fuel motor and have 78,000 miles, I changed the plugs at 50,000 and perfrom all of the maintenance as the books call. I just replaced the throttle postioning sensor as the car would stumble when taking off and would die at the stop light. After I changed it , it helped for a couple of days and now it is doing it again. Also, the trans. feels like it tis slipping and all mantenance has been done as required by the book including the trans fluid change. I was told that the throttle positioning sensor could cause all of the symptoms I have been having, so I changed the throttle positioning sensor as as I stated it helped for a couple of days and then it is doing the same thing. Thoughts?