How to access engine/firewall 02 sensor?
 

The CEL came on the other day and the result was a P0135 code.

From doing a little research this is the Bank 1 Sensor 1, which is located on the firewall side of the engine.

After peering into the back of the engine bay, it looks somewhat difficult to reach from the top without potentially breaking something else in the process (old wires and hoses). Unfortunately I just moved and my trusty rhino ramps are no longer with me, so I wasn't able to see if I can get to it from under the car.

Based on experience, is it easier to get to it from the top, or from the bottom. I don't particularly want to buy ramps again at the moment, but if it's only accessible from the bottom, then I'll go ahead and do that.

Just want to make sure I don't waste the time/money when the normal procedure is from the top and I'm just not trying hard enough :D

On a side note, I accidentally used 100% gasoline (vs the 10% ethanol mix) from a no name gas station the other day, and after maybe 50 miles or so, the CEL came on. I know its a stretch, but I have a feeling the gas was most likely very old, and "100% gas", which sounds good, but perhaps my car isn't used to that.

So, with that said, anyone have any thoughts about this? Could this potentially hurt the 02 sensor and maybe it'll normalize after I put in some regular name brand gas again? Maybe use a higher octane?

No idea if the gas mix hurt anything, but I had to replace the same sensor on my '98, and yes I did it from the bottom. Much easier that way. Besides ramps, you need a special socket. That was my experience, anyway.

I believe there are multiple variants for the 02 sensor socket. Any particular one you used that worked out well? There is a DIY for a 95 ES300, but he was able to access it from the top, so things may be different in terms of ease of access and the correct socket to use.