I recently bought a 1992 toyota 4runner and today when looking around the truck I noticed the downstream o2 sensor is just hanging beside the exhaust with no hole for it to go into. It has a really rough idle/misfire to the point it'll stall could this be the problem causing that or should I look somewher else? Any help would be appreciated

 

Yeah, if your motor is fuel injected it needs the o2 sensors to decide how much fuel to give the motor.

No sensor would definitely cause those symptoms.

 

The downstream sensor is to check if the catalytic converter is working properly. It definitely needs to be fixed though.

 

Thanks for the information everyone I just saw that while looking around and wondered if it was something major. Time to figure out why it's missing

 

That should have thrown a check engine light. If not then its worth checking out to see why. Ive had cars come in where previouse owners popped the light to sell it quick. Might be trouble codes hiding in the ecu