O2 Sensor

FastlaneV6GT · 02-13-2008, 07:58 AM

My car has about 108k miles on it, and I dont think the O2 sensors have ever been replaced. I dont have an SES light, but my gas mileage and lower RPM acceleration could be better. Plugs and wires are good and filter is clean. Think I should replace one or both?

coupe · 02-13-2008, 08:01 AM

If it aint broke dont fix it

FastlaneV6GT · 02-13-2008, 08:45 AM

I know on older cars it was part of a regular tune up...it may not be BAD, but could hurt performance and stuff. Is that the case with GAs?

coupe · 02-13-2008, 09:00 AM

It was never part of a regular tune up.
If your not throwing a code for a bad O2 sensor (or a code that can be linked to a bad O2 sensor etc.) then there is no need to replace them/it.

Just do some basic tune up items like:
air filter
fuel filter
PCV valve
plugs and wires
get your injectors pressure cleaned
check your trans fluid, make sure its the correct color and smell
coolant flush

Dont go replacing parts if you have no evidence of them actually being bad.

SSRacer · 02-13-2008, 09:59 AM

If you are just noticing this in the past few months, could just be the gas. Gas companies use different formulations in the summer and winter. I have noticed that my car seems a bit sluggish and my mileage has dropped, just since winter started. Still planning a tune up for the spring, but I'm thinking the gas formulation could be the cause.

FastlaneV6GT · 02-13-2008, 10:41 AM

It's not the gas. Mileage has been poor for a while.

Lab Rat · 02-13-2008, 11:08 AM

I believe that 100000 mile service calls for changing 02 sensors. But at 135000 I have not changed mine yet. Maybe I will start looking for an inexpensive replacement.

01GT18s · 03-05-2008, 02:45 PM

My 2001 Grand Am, has 104k, and I want to replace the 02 sensor, which one is best to replace, the one before or after the catalyc?

coupe · 03-05-2008, 03:37 PM

Quote:

Originally Posted by 01GT18s

My 2001 Grand Am, has 104k, and I want to replace the 02 sensor, which one is best to replace, the one before or after the catalyc?

Quote:

Originally Posted by coupe

It was never part of a regular tune up.
If your not throwing a code for a bad O2 sensor (or a code that can be linked to a bad O2 sensor etc.) then there is no need to replace them/it.

Just do some basic tune up items like:
air filter
fuel filter
PCV valve
plugs and wires
get your injectors pressure cleaned
check your trans fluid, make sure its the correct color and smell
coolant flush

Dont go replacing parts if you have no evidence of them actually being bad.

I still stand by this.
Even some of the things that i listed you dont need to change if there isnt anything wrong with them.

KhellendrosxS · 03-05-2008, 03:48 PM

Coupe is right. 02 sensors either work or they dont, there is no sense replacing either of them unless there is a code that would suggest they are bad.

If you feel you have to replace one the one before the cat converter is the one the PCM uses to determine if the car is at the commanded AFR. The post cat O2 sensor is just used to make sure the cat converter is functioning properly.

SSRacer · 03-05-2008, 06:23 PM

This past weekend I changed my oil and filter, cleaned my air filter and MAF, replaced the PCV calve and replaced the fuel filter (84K on it), then dumped some fuel system cleaner in the tank. Instantly noticed more pep in her step.

lvemy3100 · 03-05-2008, 06:32 PM

gonna have to dissagree with some people here...

02 sensors will foul out over time and end up reading incorrectly and therefore giving you crappy MPG... not gonna get into the technical stuff that has to do with all of this right now but if you dont know how old they are or you just have the money and doubt the old sensors are working properly go ahead and change them out... worst case you now have new sensors.. best case your car runs better... kinda seems win win to me...

02-13-2008, 07:58 AM	#1
FastlaneV6GT Representing Utah AKA: Keith Join Date: Jul 2005 Location: Provo, UT Age: 35 Posts: 249 Vehicle: 2005 Subaru Legacy GT	O2 Sensor My car has about 108k miles on it, and I dont think the O2 sensors have ever been replaced. I dont have an SES light, but my gas mileage and lower RPM acceleration could be better. Plugs and wires are good and filter is clean. Think I should replace one or both? __________________ 2005 Subaru Legacy GT Ltd- 5MT 2004 Chevy Cavalier- 2.2 Ecotec

02-13-2008, 08:01 AM	#2
coupe lick it AKA: Rand Join Date: May 2003 Location: Grand Rapids, Mi Age: 37 Posts: 7,347 Vehicle: 99 GAGT/96 Z71/05 R6	If it aint broke dont fix it __________________ CarDomain.com http://profile.myspace.com/index.cfm...endID=31690558 he has asserted his dominance over competing males with the loud masculine sound form his exaust system, Females searching for a potential mate will be driven away by weaker exaust systems and attracted to his SLP.

02-13-2008, 08:45 AM	#3
FastlaneV6GT Representing Utah AKA: Keith Join Date: Jul 2005 Location: Provo, UT Age: 35 Posts: 249 Vehicle: 2005 Subaru Legacy GT	I know on older cars it was part of a regular tune up...it may not be BAD, but could hurt performance and stuff. Is that the case with GAs? __________________ 2005 Subaru Legacy GT Ltd- 5MT 2004 Chevy Cavalier- 2.2 Ecotec

02-13-2008, 09:00 AM	#4
coupe lick it AKA: Rand Join Date: May 2003 Location: Grand Rapids, Mi Age: 37 Posts: 7,347 Vehicle: 99 GAGT/96 Z71/05 R6	It was never part of a regular tune up. If your not throwing a code for a bad O2 sensor (or a code that can be linked to a bad O2 sensor etc.) then there is no need to replace them/it. Just do some basic tune up items like: air filter fuel filter PCV valve plugs and wires get your injectors pressure cleaned check your trans fluid, make sure its the correct color and smell coolant flush Dont go replacing parts if you have no evidence of them actually being bad. __________________ CarDomain.com http://profile.myspace.com/index.cfm...endID=31690558 he has asserted his dominance over competing males with the loud masculine sound form his exaust system, Females searching for a potential mate will be driven away by weaker exaust systems and attracted to his SLP.

02-13-2008, 09:59 AM	#5
SSRacer Speed Racer AKA: Sean Join Date: Mar 2003 Location: Somewhere Age: 40 Posts: 1,440 Vehicle: 2002 Grand Am GT Sedan	If you are just noticing this in the past few months, could just be the gas. Gas companies use different formulations in the summer and winter. I have noticed that my car seems a bit sluggish and my mileage has dropped, just since winter started. Still planning a tune up for the spring, but I'm thinking the gas formulation could be the cause. __________________ 2002 Pontiac Grand Am GT1 http://cardomain.com/id/ssgohan Don't take life too seriously, you'll never get out alive. If it ain't broke, don't Microsoft it.

02-13-2008, 10:41 AM	#6
FastlaneV6GT Representing Utah AKA: Keith Join Date: Jul 2005 Location: Provo, UT Age: 35 Posts: 249 Vehicle: 2005 Subaru Legacy GT	It's not the gas. Mileage has been poor for a while. __________________ 2005 Subaru Legacy GT Ltd- 5MT 2004 Chevy Cavalier- 2.2 Ecotec

02-13-2008, 11:08 AM	#7
Lab Rat Fear the Four AKA: Craig Join Date: Jul 2005 Location: Kenosha, Wi. Posts: 452 Vehicle: 2000 Grand Am SE	I believe that 100000 mile service calls for changing 02 sensors. But at 135000 I have not changed mine yet. Maybe I will start looking for an inexpensive replacement. __________________ Lab Rat Fear the Four

03-05-2008, 02:45 PM	#8
01GT18s GAGT - Member AKA: Armando Join Date: Jun 2007 Location: Mission, TX Posts: 34 Vehicle: 2001 Grand Am GT Sedan	My 2001 Grand Am, has 104k, and I want to replace the 02 sensor, which one is best to replace, the one before or after the catalyc?

03-05-2008, 03:48 PM	#10
KhellendrosxS Im A Motherfuc*er AKA: Chris Join Date: Dec 2006 Location: Toledo, Ohio Age: 34 Posts: 1,056 Vehicle: 2001 Grand Am GT	Coupe is right. 02 sensors either work or they dont, there is no sense replacing either of them unless there is a code that would suggest they are bad. If you feel you have to replace one the one before the cat converter is the one the PCM uses to determine if the car is at the commanded AFR. The post cat O2 sensor is just used to make sure the cat converter is functioning properly. __________________ GO: 28lb/hr Trailblazer injectors, Flowmaster 80 Custom Cat-back, Stewart Warner Maximum Performance Series Gauges, DHP Powertuner SHOW: Camaro Brake Upgrade, F/R Sway Bars, SLP STB

03-05-2008, 06:23 PM	#11
SSRacer Speed Racer AKA: Sean Join Date: Mar 2003 Location: Somewhere Age: 40 Posts: 1,440 Vehicle: 2002 Grand Am GT Sedan	This past weekend I changed my oil and filter, cleaned my air filter and MAF, replaced the PCV calve and replaced the fuel filter (84K on it), then dumped some fuel system cleaner in the tank. Instantly noticed more pep in her step. __________________ 2002 Pontiac Grand Am GT1 http://cardomain.com/id/ssgohan Don't take life too seriously, you'll never get out alive. If it ain't broke, don't Microsoft it.

03-05-2008, 06:32 PM	#12
lvemy3100 Im President Charley AKA: mp Join Date: Dec 2005 Location: place Posts: 2,040 Vehicle: 01 car	gonna have to dissagree with some people here... 02 sensors will foul out over time and end up reading incorrectly and therefore giving you crappy MPG... not gonna get into the technical stuff that has to do with all of this right now but if you dont know how old they are or you just have the money and doubt the old sensors are working properly go ahead and change them out... worst case you now have new sensors.. best case your car runs better... kinda seems win win to me... __________________ -Mark You want more power? You need MP Racing! ------ Now drink with me deeply of the bourbon, scotch, and rye until such time as we are fighting drunk. Then we shall find, and beat the a**es of, the nonbelievers who ruined my feast.

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