When driving at highway speeds, I can smell exhaust inside the truck. It seems like it is worse with the windows down. There is a check engine light on but it runs completely fine.
My car has 95000 miles.
My car has an automatic transmission.
It sounds like one of two problems: an exhaust leak or a faulty catalytic converter. Inspect the exhaust system for rust or holes. If you see a hole, a qualified muffler shop should be able to weld in a new pipe. If this is not the issue, they will also be able to test your catalytic converter and replace it, if necessary. It is crucial to have a professional perform any welds to the exhaust system because any holes would mimic the same issue.
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