I own 2011 Buick Enclave that started engine light goes on and off and can not clear error code p0008. I have only 72000 and little problems so far. The gas mileage has been poor lately 11mpg usually 14/15 in the City. Should I be concerned about timing belt stretched even though engine sounds good? Should I be looking for a replacement, I wanted to wait one or two years. GM recalled 2009 models no luck so far with other years.