so i just got my 5.0 with the standard transmission, i have just recently noticed when im accelerating from a stop, in first gear if i get to about 3k rpm my tach says " SHIFT 1->4 FOR FUEL ECON" and it seems like it actually locks me out of 2nd gear, i pull hard left and down and i feel it slide right into 4th? is this some type of fuel saving thing they installed and how do i turn it off? lol thanks