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o2 sensor question

  • Thread starter Thread starter ASchaffer
  • Start date Start date Jun 23, 2004
A

ASchaffer

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Oct 8, 2003
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Tampa, FL
Jun 23, 2004
#1
  • Jun 23, 2004
  • #1
If my o2 sensors behind where my cats should be were messed up, would it make my car run bad, or would it just trigger the check engine light?
 

Carl

Founding Member
Aug 7, 2000
613
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Johnson City, TN
Jun 23, 2004
#2
  • Jun 23, 2004
  • #2
You might get some stuttering and hesitation, less fuel mileage. It will probably be a little down on power, but nothing drastic.
 
A

ASchaffer

New Member
Oct 8, 2003
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Tampa, FL
Jun 23, 2004
#3
  • Jun 23, 2004
  • #3
ya when im accelerating slowly it stutters, and doesnt sound good... So o2 sensors would cause this then?
 

Carl

Founding Member
Aug 7, 2000
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Johnson City, TN
Jun 23, 2004
#4
  • Jun 23, 2004
  • #4
Yes, they could. That's not saying that it definitely is, but yes they could. Your car is probably running excessively lean or rich if your o2 sensor is bad and that gives you stuttering and hesitation problems.

Does your h-pipe have cats or not? If you are getting a check engine light with o2 sensor codes then if you have mil elim's then one is probably bad or if you do have cats if they are high flow you could trigger a light also. But if you have no Check Engine light, it could be something as simple as bad gas
 
A

ASchaffer

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Oct 8, 2003
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Tampa, FL
Jun 23, 2004
#5
  • Jun 23, 2004
  • #5
My H-Pipe has no cats... I did the do it yourself MIL Eliminators, maybe I didnt do a good job. These have been working fine for about 3 weeks now. Could that possibly be the problem here?
 

Carl

Founding Member
Aug 7, 2000
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Johnson City, TN
Jun 23, 2004
#6
  • Jun 23, 2004
  • #6
That's probably exactly what it is. If you have a bad connection or one of the components go bad, it's gonna give you that code. Also, some cars just don't respond well to those MIL's. Mil Elimanators work most of the time, but there are still cars out there that go through several sets and they still get the light anyway. Try reseting your battery and see if it comes on again. I know they have more of a tendency to come on in cold and wet weather and stay off in hot weather, if you occasionally get the light due to Mil Elim's.
 

jstreet0204

Active Member
Jun 26, 2003
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36
Winston Salem, NC
Jun 23, 2004
#7
  • Jun 23, 2004
  • #7
ASchaffer said:
If my o2 sensors behind where my cats should be were messed up, would it make my car run bad, or would it just trigger the check engine light?
Click to expand...

No, front o2's affect performance, rears do not. The rear o2's are only there to test the function of the cats.
 

Milenko

Skid Mark Layer...only not fro
Founding Member
Nov 5, 2001
462
1
19
Boston, MA
Sep 1, 2004
#8
  • Sep 1, 2004
  • #8
jstreet0204 said:
No, front o2's affect performance, rears do not. The rear o2's are only there to test the function of the cats.
Click to expand...
I know I'm bringing back an old topic, but I need to.

If the front O2s are messed up, would this affect your car? Mine is hesitating and bucking, and it happened after I got my O/R X installed.
 

RysRed96GT

I like it FURRY!!!
Founding Member
Apr 9, 2001
3,207
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56
Pasadena, MD
Sep 1, 2004
#9
  • Sep 1, 2004
  • #9
jstreet0204 said:
No, front o2's affect performance, rears do not. The rear o2's are only there to test the function of the cats.
Click to expand...


the rears are only there for emissions purposes to throw the dummy CEL if the cats are bad (or missing). they have no effect on performance and arent read into the EEC for controlling air/fuel. the fronts, however, do. other things could cause the problems you indicated, but if you have high miles, then replace them. call randy at liberty ford and you can get oem's for 66 bucks each. i'd also check your MAF sensor if it's dirty. how is your idle?
 

RysRed96GT

I like it FURRY!!!
Founding Member
Apr 9, 2001
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56
Pasadena, MD
Sep 1, 2004
#10
  • Sep 1, 2004
  • #10
this seems like an old thread. im reading ur other one and u said the o2's are unplugged?

mass air sensor (maf) is the collection tube inline with the inlet tube and the air filter. the sampling tube inside can become dirty and cause a rough idle and labored acceleration. its a quick thing to clean it. but ya gotta break the tamper proof pins to do it (use a power drill/bit and torx t20 bit)

edit: why is my post above yours?
 

Milenko

Skid Mark Layer...only not fro
Founding Member
Nov 5, 2001
462
1
19
Boston, MA
Sep 1, 2004
#11
  • Sep 1, 2004
  • #11
RysRed96GT said:


the rears are only there for emissions purposes to throw the dummy CEL if the cats are bad (or missing). they have no effect on performance and arent read into the EEC for controlling air/fuel. the fronts, however, do. other things could cause the problems you indicated, but if you have high miles, then replace them. call randy at liberty ford and you can get oem's for 66 bucks each. i'd also check your MAF sensor if it's dirty. how is your idle?
Click to expand...
My idle isn't too much different, but it is. Off by about 2-300 rpms.

Idling sort of rough too. I unplugged the battery for 20 mins and the car drove like normal, so I don't know.

Where's the MAF sensor? Is it connected to and/or near the air filterr?
 
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