2006 Buick Lacrosse, CXL, 78K miles. 6 months ago, the check gas cap message came on. The gas cap was replaced. The message is still on. Soon after, the engine light came on as well. The Buick dealer said (without running a diagnostic or looking at the car) we needed to replace the catalytic converter and it would be expensive! Had 2 diagnostic tests run - one at a garage and one at an auto parts shop. No codes were detected.
Whenever the car is close to its 3k oil change, an “'oil low” message appears. The oil has never been low, it’s an annoying message to get the oil changed. As the gas cap/engine light came on shortly before its 75K mile check, could this be the same case?
The car runs great and there has been no change in gas mileage.
Can anyone help?