2002 Trailblazer LTZ 4.2 throttle body only partially opens. At full throttle scanner shows APP at 100% but TPS at 30% and is not in reduced power mode and there are no codes. Suspected throttle body. Removed it, put it on my 2005 LS 4.2 and it works fine. ECM? - Wiring? Has anyone had this problem?