I have recently purchaed a 99 V70 FWD 94k miles. Runs great but 2 weeks ago the Check Engine came on indicating a bad front O2 sensor. Before it was replaced the car started to stall during startup. Outside Temp was in the mid 30's and rainy. Did it a few times from a cold start and also after driving 3-5 miles to go to the store. Car would sit 5 min with engine off and stall upon startup. It catches after several times and runs great after that. Replaced front O2 sensor and car continued to stall even as the outside air temp went to 50 and dry condtions. Check Engine light now comes on 5 min after codes are zeroized. Code now reads rear O2 sensor and Manufacture Fuel Contol Metering in that order. The car does not idle surge when stopped or while driving. My Mech says it is running rich and will need a new Throtle Body for about $1000. I am in the process of checking the fuel milage to see if it is out of whack. Does it just need to be cleaned or replaced?

Help!!