Hello, I have a 1993 320i and my fuel consumption is really bad, I have filled the gas tank to full with premium fuel and all I have driven it is 4 kilometers 2.4 Miles and I am almost at 3 quarters of a tank left, what could be causing this? I have already replaced the Fuel Pump, Fuel Filter, Spark plugs although when replacing them I noticed a rust coloured sort of build up on one of the ignition coilscrankshaft position sensor, and my mass airflow sensor and my car does not start up easily, I am also aware that my valve cover gasket needs to be replaced because I can smell the oil burning, could a bad O2 sensor be the cause of the bad fuel consumption thanks.

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This could be a fuel leak or an engine misfire. If the engine is running poorly, check each cylinder for a misfire. If you locate a misfire, check for spark, fuel injector pulse and compression on the bad cylinder and a few good ones.

- Nick