I was wondering if anyone here has ever replaced the o2 sensor in a 1991 lx 2.3 mustang. I have tried to take my old one out, but the darn thing just won't budge. Any advice?

 

Remove the negative battery post. Spray some PB blaster on the threads and let it sit for about 15 - 30 minutes. Then run the motor until it gets to operating temp. Then very carefully (so you don't get burned ) use a Oxygen sensor socket or if you got the room, a 1" (I Think) wrench to remove it. Do not use jerky motions to get it to turn or you could strip the bung out. Should come out ok. When you put the new one in make sure it has anti-sieze compound on the threads and don't touch the sensor. Good luck!