grussimo

2007 Suburban 5.3 Flex, cel on, service stabilitak, hard shifts resolved! For my application, I had a lean bank1 & 2 code (P0171,P0174) and hard shifts, intermittant.... only when stabilitak warning occured. It was an intake leak.... the hose connected to the drivers valve cover cracked. Apparently anytime the stabiltrak warning occurs (many, many possible errors), the default is maximum line pressure and hard shifts. FYI, I deleted the AFM feature, both in the ECU and mechanical. Replaced cam, non-afm lifters for all cylinders, and non-afm valley cover. No noticable differnce in mpg.