Hey folks I have a bit of a problem now. I failed a smog pre-test On my 90 gtus n/a/ Everything else is fine but my NOx it thru the roof. Either I have alot of carbon build up or my engine is on its way out. Im thinking its the carbon build up. Whats recommended to clean it? Steam cleaning? Seafoam? The stuff Mazda sells for 50 bucks a bottle to clean the engine? Also the tech said my engine is ping-ing. Sigh*
