I was trying to see how hard it is to change the o2 sensor on a 94 accord 5-speed any help would be appreciated

 

They can be a major pain to remove, all the cycling of heat and exposure to the elements can really make things difficult. They make special sockets for the job. (http://www.pelicanparts.com/catalog/...lder/4491B.jpg)
(http://www.harborfreight.com/media/c...mage_23171.jpg) The idea is applying the maximum amount of torque to the faces of the sensor because the threads are gonna be stuck (your looking at least 50-60 ft. lbs. of torque to get anything moving and that is a best case scenario) , you may need a torch to heat the area around the threads. Also check the connector to see if it is a match to your new part before you go tackling the job.

I'm not sure where you are at with the diagnosis or issue but just a heads up, a engine trouble code for a sensor can also be a fuel and air management problem, a bad catalytic converter or even an exhaust leak. A lot of garages will say you need the sensor, replace it, clear the code then only to have the code come back, but don't get me wrong, sensors do fail.

 

If it's hard to remove you could also try running the car for a while and try to loosen it then, it will be hot just don't burn yourself.

 

Yeah, you;d be surprised what it would take though for the exhaust to heat up the threads enough though. Even at full operating temp, I'd say your looking at maybe 450 degrees fahrenheit at the sensor's location where as a torch will get you in the thousands and even that sometimes isn't enough. That being said, if your without any other means of assisting it's removal, running the car won't hurt, unless of course you burn yourself haha, good catch there.

 

I just did this last weekend on a '94 accord lx 2.2L 5spd. It is super easy, but as others mentioned the sensor can be stuck in there pretty good. I used a little bit of PB blaster to free it up then used an o2 sensor socket to remove it. Make sure you get a socket that has the slit ALL THE WAY through the side, not just part way... That makes it way easier to do without screwing up the wiring on the new one. Get a short one, not a deep socket, as it'll be much easier to apply more torque without the socket slipping off.

If you use a penetrating lube like PB Blaster to loosen it, clean it out with a rag before installing the new one. DON'T use a silicone lube, that will ruin the new sensor if it touches it.

If it's REALLY stuck, try applying heat. Once you remove the old sensor, ensure that the threads in the manifold are okay. If they're a bit messed up, you may have to get a tap and run it through to " clean up" the threads before installing the new sensor.

Make sure you thread the new one in by hand to ensure you don't strip the threads, then use a torque wrench to tighten it. If I recall correctly it should be torqued to 33 ft-lbs, but check that for yourself to be safe.

The above are mostly just precautions... The whole thing went very smoothly for me, even though it did take a bit of muscle to pop the old sensor loose. The job isn't hard at all, as long as you have the right o2 socket and a torque wrench you'll be fine!

Edit: The OEM manufacturer for our car is Denso... Get a Denso sensor and save yourself the headache of a different brand sensor outputting the wrong voltage. Just check if you need a sensor with a male or female connector. Mine is female but I'm not sure if that's the same for every car of this year/model. Mine cost $60 including same- day delivery locally, but RockAuto has them for $30 or so if you can wait a few days. It also might be a good idea to put some anti-seize compound on the threads of the new sensor prior to installation so it doesn't get frozen in there as badly (in case you ever need to remove it).