Just like around the block...Not far at all. Certainly not a day! If you order a new 02 sensor, there's 2, upstream & downstream. The one behind the engine is upstream. Unplug the one you're running now, and look at the plug real good, take a picture even. Some websites will list multiples as an "exact fit". The difference is that the pins are in different arrangements. Most websites have multiple views of their sensors. They all look the same from the side. Find a straight on shot into the plug end, and zoom in. They're in a square, but some have a tab or two that won't mate up correctly. If you buy it in person at a store, bring the old one with you to match'em up.
