It is very likely that all you need is to clean your Throttle Body (TB). Search on this site to find out how easy it really is to do it yourself & save a bunch of money.
I also have a 99 SE with a V-6 & AutoZone told me to replace O2 sensors. They were full of it. Cleaned my TB & everything was cool.
Did they tell you what the code numbers were? Find out, then do a search for the P0402, or whatever number they give you & you'll lean a bunch about your car & how to maintain it yourself. Again, you'll save lots of money. We can even teach you easy ways to reset your CEL.
