hi everyone & thanx for tryin to help in advance ... so I got this 85 4runner 22re i went to smog an it didnt pass I put a new o2 in and passed but noticed it had a miss, It never missed with the old o2 (but the old one was shot it was original from 85). I unpluged the new one an it ran perfect then plug it in and it started to have a miss again. Then I go and exchange it for another one which is bosch, same thing with the new one so I say bosch must be junk so I got a denso and same thing so its not the o2 sensor itself must be something in between. I dont even know where to start im thinking probably injectors but they all got new seals an caps an when its cold befor it warms up it runs perfect, I know its in open loop pre programmed till its warm. I put in a new tps ,coolant temp sensor , the truck runs perfect with the o2 unpluged... I read a thread on here where he had similar problems and it was his injectors I also experienced injector problems in my 92 3.0, I don't think this ones injectors. Well sorry so long and probably confusing... my brain hurts it seems so easy....

 

Some knowledge be cool....

 

nothing yet...

 

ok let me try again, the truck is running im holding the throttle open maybe 1500-2000 rpm with the o2 unplugged and its running perfect then while im doing this i plug in the o2 (pretty tallented) and instantly it starts missing. this is a denso o2 brand new i also tried 2 bosch o2 that were brand new and same $**!. I dont know i put my volt meter on the wire coming from the truck with the key on an it reads 4 volts i really dont know how to test this....

 

I would say just keep it unplugged and when its time for inspection just plug it up. and while its unplugged wrap tape aroud the end and use a zip tie to hold it up

 

Do you have a noticeable exhaust leak anywhere? If you dont, check for leaks before the O2 sensor.
Is it like an entire cylinder is missing or just a stumble?
Take the spark plugs off one at a time to try and figure out which cylinder is missing.

 

Na if I leave it disconnected then I get crappy mpg. No exhaust leaks, its more of a stumble and u hear popping out the exhaust kinda like a burnt valve but its not...I took all plug wires off one at a time and it ran worse....

 

So will the fuel damper/pulsator thing give me this problem? Also the lil screw that's is in the hat that's on the damper should be screwed in it or? This is confusing me im going to exchange the o2 for another one but keepin it denso just to see but it will be the 4th one...... im tryin to figure out where that single black wire for the o2 goes..... I been searchin all over for hints/ideas/help to figure this out but there's alot of dead threads that don't help....its gotta be somethin simple... 4crawler where u at u seem to know your $***.....

 

Hi- I am a new user and thought I would jump in on this thread about 02 sensors. Mine had a ground wire attached to the wire coming from the sensor to the wire harness. The gound wire was obviously added aftermarket and went to the fender wall. I took the ground wire off and did not notice a difference. Is there any reason to have that wire grounded?

 

no clue..

 

What should the gas mileage be on a vehichle like this?

 

So I found what should be the problem the po cut the o2 wire along the fire wall in the harness... now the main black wire an the wire mesh/net that covers it are both cut and spliced back to each other. I feel that's wrong, ill put up pic... it jus seems like no one knows anything about this subject...