NHTSA Complaint #10849676 — 2006 GMC ENVOY DENALI

FAILURE OF THE DOD LIFTER, ALSO KNOWN AS THE ACTIVE FUEL MANAGEMENT SYSTEM. WHILE AT SPEED ON THE FREEWAY, THE DOD LIFTER ON CYLINDER #7 FAILED CAUSING A MISFIRE ON THE CYLINDER WHICH CAUSED TEH ENGINE TO SHAKE VIOLENTLY. THIS IS THE 2ND FAILURE OF A DOD LIFTER ON MY TRUCK. IN NOV 2014, A DOD LIFTER ON CYLINDER #6 FAILED, CAUSING A ENGINE MISFIRE AND A VIOLENT SHAKE. THE CAUSE OF THE FAILURE WAS DETERMINED TO BE LACK OF OIL PRESSURIZE THE DOD LIFTER. UPON DECIDING TO REBUILD THE MOTOR RATHER THAN REPLACING THE MOTOR, WE DECIDED TO REPLACE ALL INTERNAL COMPONENTS OF THE MOTOR SIMPLY BECAUSE THE MOTOR WOULD NEED A FULL TEAR DOWN ANYWAY. THE LIFTERS, OIL PRESSURE SOLENOIDS OF THE DOD LIFTERS, ROCKERS, ROCKER ARMS, SPRINGS AND CAMSHAFT WERE ALL REPLACED THINKING THAT WE MIGHT AS WELL REBUILD THE BLOCK WITH NEW COMPONENTS TO SAVE OFF ANY FUTURE ISSUES. AFTER 1 MONTH IN THE GMC SERVICE CENTER, THE VEHICLE WAS BACK ON THE ROAD IN DEC 2014. THIS REPAIR WAS $5,900.00 IN MARCH 2016, YES 14 MONTHS LATER, A 2ND FAILURE OF A DOD LIFTER OCCURRED ON CYLINDER #7. THE VEHICLE EXHIBITED THE SAME ISSUES AS IN NOV 2014. THIS FAILURE OCCURRED ON THE REBUILT MOTOR ON NEW COMPONENTS INSTALLED IN NOV 2014. THIS REPAIR WILL COST $2500 JUST TO REPLACE THE 1 LIFTER. NO OTHER COMPONENTS. THIS LEADS ME TO BELIEVE THAT A THE DOD FAILURE IS MORE COMMON AND IS A DESIGN FLAW OF THE ACTIVE FUEL MANAGEMENT SYSTEM. THIS ISSUE IS MORE THAN A TSB ISSUE, IT SHOULD BE A RECALL.