my car is running very rich and i can smell fumes thoughout the car when driving on 1993 Volvo 940

when i start out i have to depress the pedal to the floor it putts and sometimes back fires and then it runs fine on the interstate but in the city it hardly ever gets out of first gear, i've had a tuneup , transmission serviced air filter changed. please help some think its my maas air flow and some say o2 sensor
dave williams

Asked by for the 1993 Volvo 940
I forget the year range Volvos affected but the MAF sensors did have problems due to a little thermostat in th air filter housing failing and diverting hot air all the time across the MAF. With the engine warmed up look for the flat at the bottom of the housing it should be closed and not letting hot air past. Try cleaning the MAF sensor with CRC product # 05110