Hello everyone..need some help on this one..I have a 1991 W124,4 cylinder,fuel injection but no cat. convertor. I am experiencing a very perculiar situation and that is each time the engine is running or car is parked..I am able smell of petrol coming from the left rear section of the car ..what could the problem be? Also what is the recommended CO% level for the W124. Thanks in advance for your contribution.