O2 sensor

[kywildcat]

New to the forum, but longtime 4Runner owner. I have a 96 with the 3.4 V6. Recently had the engine light to come on and the code came back the upstream O2 sensor. Replaced the old one with a Bosch OEM that even the clip matched on. Had the computer cleared and have driven it several hundred miles to give the computer time to make the adjustments, but the mileage is horrible. Took 5 gallons to make a 60 mile tip and its not getting any better. Just wonder if anyone else has had this same problem. Thanks in advance.

 

[kball]

Lol, I wouldn't use Bosch and OEM in the same sentence around here unless you like it hot :flamethrwoer2:

Stick with Denso which is the real OEM.

Check this link for the part number you need.

Oxygen / AFR Sensors - Underdog Racing Development

 

[ShannanC]

Lol, I wouldn't use Bosch and OEM in the same sentence around here unless you like it hot :flamethrwoer2:

Stick with Denso which is the real OEM.

Check this link for the part number you need.

Oxygen / AFR Sensors - Underdog Racing Development

I agree. Bosch sucks balls. Use Denso and NGK. You can get the Denso O2 sensor from Amazon for around $65.

 

[kywildcat]

Ok, I caved under the pressure and replaced the Bosch with the Denso. Have only driven it a few miles. Any ideas on how long it is before I can see a difference? Thanks for setting me straight!

 

[kball]

You should probably unhook the battery to reset everything and let it relearn with the new sensor. It will take a few start/stop cycles for the computer to go through the system checks. 50-100 miles should be good.

 

[ShannanC]

You should probably unhook the battery to reset everything and let it relearn with the new sensor. It will take a few start/stop cycles for the computer to go through the system checks. 50-100 miles should be good.

I concur.

 

[ShannanC]

You should probably unhook the battery to reset everything and let it relearn with the new sensor. It will take a few start/stop cycles for the computer to go through the system checks. 50-100 miles should be good.

I concur. Leave battery unhooked for 15 minutes or so. ECU will relearn and all should be fine.

 

[fenrisx]

I had an o2 sensor blow/get knocked off the exhaust last winter. At the same time my a/f sensor went bad & I was getting extremely horrible mileage.

Could it be possible his a/f sensor is bad without throwing a code? I would say maybe a dirty maf, but it would be odd that it just started causing mileage when he changed the o2.