O2 sensor bad= poor gas mileage

cre · 02-06-2012, 08:53 PM

What you describe isn't consistent with a bad O2 sensor.... It's more consistent with a bad AFM, excessive engine knock, bad knock sensors or wiring, etc.

Have you bother pulling the diagnostic codes? If you don't know how look in the MKIII FAQ section for a thread on how to do it.

Conga1991 · 02-06-2012, 10:36 PM

Yes I have, I have a code 34 and 41. I just remembered I pulled the cps out and didnt jump the terminals for timing. Ill jump it, start it and see if there is any codes after that and let you know.

cre · 02-06-2012, 11:38 PM

34 is most likely the issue and timing isn't going to cause it.

Conga1991 · 02-10-2012, 11:29 PM

Okay, I'm using the stock 7mgte afm but with the Lexus electronic. Is testing the resistance on the Lexus the same as the stock 7mgte meter? Of course Im testing it now to make sure its in spec, if it is the same as the 7mgte's.

Im also running an upgraded ct-26 with a 57 trim.

cre · 02-11-2012, 12:15 AM

Yes, the actual sensor is the same... Same part number even. The method of testing in the TSRM isn't 100%... You'd need an oscilloscope and Toyota's advanced diagnostic publication to really test it. Has the air bypass screw been tampered with?

Conga1991 · 02-11-2012, 05:00 AM

I couldn't tell you... the screw is 3/4 of the way in looking into the chamber. Not sure if that helps or not.

cre · 02-11-2012, 06:46 AM

If you can see the screw, then the pressed in cover had to be drilled out and it's most like been screwed with (hehe.... pun)... See my thread in the FAQ on how to reset it to it's factory position. This isn't going to be the source of your error codes but may further contribute to fueling issues (especially if it's in further than spec).

02-06-2012, 08:53 PM	#1
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	What you describe isn't consistent with a bad O2 sensor.... It's more consistent with a bad AFM, excessive engine knock, bad knock sensors or wiring, etc. Have you bother pulling the diagnostic codes? If you don't know how look in the MKIII FAQ section for a thread on how to do it. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

02-06-2012, 11:38 PM	#3
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	34 is most likely the issue and timing isn't going to cause it. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

02-11-2012, 12:15 AM	#5
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Yes, the actual sensor is the same... Same part number even. The method of testing in the TSRM isn't 100%... You'd need an oscilloscope and Toyota's advanced diagnostic publication to really test it. Has the air bypass screw been tampered with? __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

02-11-2012, 06:46 AM	#7
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	If you can see the screw, then the pressed in cover had to be drilled out and it's most like been screwed with (hehe.... pun)... See my thread in the FAQ on how to reset it to it's factory position. This isn't going to be the source of your error codes but may further contribute to fueling issues (especially if it's in further than spec). __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
gas mileage on NA 87 supra	jason7504	MKIII Supra	3	04-05-2010 01:20 AM
Toyota Supra Twin Turbo Auto Black Low Mileage 39000 One Owner (1993)	Yagga	Buy/Sell Cars	0	02-26-2010 05:15 PM
gas mileage?	supfoo514	MKIII Supra	26	09-29-2007 08:16 PM
hesitation, high cold idle and poor gas mileage	sd88supra	MKIII Supra	14	02-06-2007 04:17 AM
Gas Mileage	MacDrevi0us	Non-Generation Specific Questions	1	06-09-2006 03:51 AM

02-06-2012, 10:36 PM	#2
Conga1991 3" Exhaust Join Date: Jun 2009 Location: Avondale, AZ Posts: 169	Yes I have, I have a code 34 and 41. I just remembered I pulled the cps out and didnt jump the terminals for timing. Ill jump it, start it and see if there is any codes after that and let you know.

02-10-2012, 11:29 PM	#4
Conga1991 3" Exhaust Join Date: Jun 2009 Location: Avondale, AZ Posts: 169	Okay, I'm using the stock 7mgte afm but with the Lexus electronic. Is testing the resistance on the Lexus the same as the stock 7mgte meter? Of course Im testing it now to make sure its in spec, if it is the same as the 7mgte's. Im also running an upgraded ct-26 with a 57 trim.

02-11-2012, 05:00 AM	#6
Conga1991 3" Exhaust Join Date: Jun 2009 Location: Avondale, AZ Posts: 169	I couldn't tell you... the screw is 3/4 of the way in looking into the chamber. Not sure if that helps or not.