This is for my 03 Ranger, not my Mustang.

I'm throwing a code for O2's. There's 4, 2 pre cat and 2 post cat before the Y pipe. the front one on the right bank is between the block and ac compressor and there's really no way to get it off without unbolting the plumbing from the manifold. Is there any way (emissions be damned) that I can fool the computer? Like can I plug up a new O2 sensor and ty wrap it up into the wheel well or the frame?

 

While you can do that, I wouldn't advise it. your gas milage will go to crap and you will get a code for a lean condition. The o2 reads oxygen in the exhaust and the computer uses that reading to determine whether it needs to add more or less fuel to make a good air/fuel mixture. If the O2 sensor is not in the exhaust pipe it will only read oxygen and the computer will think the motor is running lean, and will dump more and more fuel into the mix to correct it, but it never will correct the problem. So once it maxs out how much fuel it is allowed to add it will throw a lean code.

I'd first make sure that the problem really is the O2 sensor. It could very well be a wiring issue or exhaust leak which may be easier and much cheaper to fix. Otherwise, I would try to figure out how to replace the faulty O2 sensor correctly. Maybe use a crows foot, swivel extension and/or similar tool(s) to remove it.

Good luck...