I know there are many threads on this but again any advice would help. Just fitted a secondhand engine with related standard ecu (this engine came from a reliable source so I know theres no problem with the engine itself) but when it warms up to temp is running at around 1200/1300 rpm the engine drives and pulls well but does seem to be over fueling as you can smell this from the exhaust and also when driving burnt fuel is causeing bangs/flames from the exhaust any help would be appreciated thanks