Q: Smoke coming out of tailpipe

Hi there. Excessive smoke can indicate some serious issues. The first thing to do is to determine the type of smoke that is emitted. A whitish smoke would indicate engine coolant entering into the combustion chamber. This can cause rough idle and you may notice that coolant is being consumed, a common cause is a failed head gasket, worst case scenario would be a crack in the cylinder head or block. A bluish, thick smoke would indicate oil is being burned in the combustion chambers. Also, faulty valve stem seals, excessively worn valve guides, or piston rings can also lead to rough idling. You may notice you have to add oil more often. If the smoke is black, this could indicate excessive or unburnt fuel. The fix could be as easy as an injector service or you may have one or more faulty fuel injectors or contaminated fuel. In any case, you may want to enlist the assistance of a mechanic, such as one from YourMechanic, to inspect the smoke issue and replace any failing parts.