Have a code P0107 comes on I reintermittently,seems to have reduced fuel milage.

What is your question?

Code reader says MAP low voltage. Wheres MAP located on 2007 Trailblazer 4.2 L engine. I reset code might drive few hundred miles before comes again same code P0107. Any one have a clue whats going on? Mileage 55,063.