oxygen sensor

[ammarghazi]

hello all...
I am in desperate need for help!! I own a merc 300se 1990. In the last year i started having trouble with the engine! It starts nicely when cold! but after it warms up engine cuts out and is v.difficult to start again without foot on the peddle. I have replaced the idle adjuster,plugs,plug leads,coil,co2 adjustments,cleaned distributor,cleaned injectors,but the problem remains!! I like to try and fit a new oxygen sensor!maybe it will solve my problems,but i can't find it!! I am not sure if my car is fitted with a catalic converter or not.I have looked under the car and found three barrels but nothing attached to them! then i tried finding it on the manufold,but still couldn't find it.If anyone understands what i mean PLEASE HELP!!!