UnPlugging the O2
 

ok so i have a 91 4runner with the 22re. i know the truck is running rich really rich like 16mpg rich, and my exhaust is crap full of rust holes. Which makes me think it's my o2 sensor sending the rich command consistently. So if i unplug the o2 sensor it should run on the factory determined amount of fuel. Now I plan to redo the exhaust in about 2 weeks and was wondering if anything bad could happen if i unplug the o2 until then to see if my mileage improves.

Is the CEL coming on?

no cel yet

You would probably have a CEL if the O2 sensor is bad....and unplugging it would probably throw a code as well. If your getting new exhaust in 2 weeks I'd just leave it, and deal with it a bit longer.

Taking the O2 sensor out will give you worse gas mileage, It took me over a month to trace my O2 sensor wire, the truck was run for awhile with no o2 sensor it clogged up the cat

Ya if u take the 02 out of the mix you will be worse off believe me

my cat is crap to start with

Your truck is going to run worse if you remove the O2 sensors.....regardless if the cat is already shot.

without the o2 it should go into limp mode, and will bareley even be drivable.

with a number of exhaust holes it probably is running pretty rich. best bet is just to suck it up until you can get the exhaust replaced.