On 4-5-06 I was charged $80.00 for a "diagnostic test" for "service engine soon" light. In fact they advised me prior to the test that a loose gas cap could cause the problem. Instead of "checking the gas cap", they went ahead and performed the test and then informed me it was due to a "loose gas cap". Upon arrival home I called three Buick dealers and was told that had they simply "put the gas cap back on tight" the "service engine" light would extinguish itself after... read full review »