I have a 2003 silverado and am having issues. When i first start truck it will miss and sputter and idle will fluctuate for 10 to 15 seconds then will smooth out. when on road at WOT it loses power, feels very restricted, rough runs, misses and the check engine light comes on. Pull code and it is p0151 and p1031. the o2 sensors have been replaced. Any clues as to what i could look for? Could a leak in the intake cause that or a bad fuel pressure regulator? HELP!!!