Bucking and excessive fuel consumption on 1996 toyota celica gt?

When driving at low speeds (usualy in traffic) or when i come off the throttle, the car bucks and jumps ive also noticed im using a lot more fuel lately. when i reset the ecu the problem dissapears, normaly 4 a week or 2. cud this b down 2 the air temp sensor as the 1st time i noticed the bucking i found it hanging in the engine bay and when i plugged it back in it cured the problem temporarily. plz help as its driving me nuts.