98 Ford explorer check engine light

Now this is getting redundant!!!! I have a 98 ford explorer sport. I got my car "diagnosed" at auto zone and they said my oxygen sensor in bank 2 was bad. I replaced it and the light went out and i drove 180 miles. It came back on. I went back to auto zone and they said it was tat same sensor. I checked it and made sure i had it in right. It looked good so i checked my egr sensor and decided to replace it. So what's wrong? Is there more than one oxygen sensor in bank 2? and i noticed the o2 sensor has a grey wire, a black wire, and 2 white wires. does it matter which white wire is connected to the corresponding white wire or can they be interchanged. And what else can cause the 02 sensor to report an error.PLEASE HELP!!!!! Thanks in advance. U can email me at [email protected]

i was on hear a few months back and a guy gave me some helpful info it may still be on here about the light it was something under the spare tire under the truck a cylinder valve or something that has been rusted from road water and such and the valve is rusted open or closed so i havent checked mine to lazy but you can pull your tire off and look to see if there is some rust anywhere on anyparts under there hope this helps