My car has 164850 miles.
My car has an automatic transmission.
Hello there. Engine knocking is a serious problem with your 2006 Chevrolet Trailblazer. The most common cause of engine knocking is low engine oil. You did well by replacing the oil first. Other likely causes of engine knocking are low oil pressure, bearing damage, pistons failing, wrist pins, or engine rods. All of these are rather serious and generally lead to the engine being rebuilt. A qualified technician, such as one from YourMechanic, will be able to diagnose your engine knocking and advise you on any repairs needed.