Symptoms of bad O2 sensors? What do you think is wrong?

91LX_5L

Founding Member
May 13, 2002
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British Columbia
I get about 120 miles to the tank.
Car tends to run rich.
Get small burps/backfires if I rev it up then let off gas and hit it quick again.
Tends to hesitate when I accelerate fairly hard (takes like 1/2 second to pickup)
When I first start it up it hunts for a idle and stalls sometimes.
seems that it should have some more power.

I have H/C/I, I dont think they have ever been changed? Have 45,500 miles on it. Can you clean them or do you need new ones?

Have new fuel filter, cleaned maf, air filter is good, plugs wires low mileage on them. Cap and rotor mabye could use a replace?

PS: Whats involved in changing them, just unbolt the old ones and put the new ones in, wiring right there or do i have to remove H pipe or what?

THANKS
 
Yep, get under the car, unsnap the quick connectors, unscrew the sensors and reverse the process to replace. Symtoms are what u dscribe. I am having the same issue. Car goes....errrr nnn putt putt putt POP! runs rich, won't idle right, blows out smoke.... I think I killed my 02's with the rich tune and having it re-tuned.
 
If you go to swap them, be prepared that they will be seized in there. Something along the lines of a 22mm box-end wrench fits them (I dont like O2 sensor sockets).

You can check each one for switching and amplitude. After the engine has run for two mins, look for the signal to read 0.1 - 0.9 volts, and switch atleast once a second (the voltage will toggle back and forth, from lean to rich).

Good luck.
 
I think ill change them, i dont plan on selling my car so new parts are new parts, less to change down the road, ill try to get the codes still and get back to you guys.

Ignition Module how long does it usually last im at 45k.
 
Ig module should be ok for awhile (but you never know). The PIP is more prone to failing but you should have another 45K miles in yours (atleast).

Good luck.
 
my check engine light came on when mine went out. if yours is not on chances are they are not the problem. is your egr hooked up? those are the problems i had when i tried deleting mine. as others mentioned i would get the codes pulled before you start spending money replacing things.
 
yeah good call thanks, gonna go by my buddies work and pull the codes, ill update this evening. but if it happens to be O2s does brand matter, assuming yes but you never know...?

someone mentioned it could be the IAC, I have cleaned it before but what do you guys think about that?
 
My engine light has never came on?

UPDATE WITH CODES

Codes it threw:

314 - Thermactor Air System Not Working - Bank 2
311 - Thermactor Air System Not Working - Bank 1

Which appears my air pump isnt working properly. What im going to do is order a smog pump eliminator kit (allows me to run stock belt right?), remove all that emissions stuff and plug the back of my heads (remove bolt and weld it).

I think I might try the IAC then?
 
What im going to do is order a smog pump eliminator kit (allows me to run stock belt right?), remove all that emissions stuff and plug the back of my heads



yes exactally what i did.yes you will run the stock belt with the delete pulley...i would remove the smog equip. as long as you are not require to pass emmissions testing...click on link below it will tell you step by step instructions how to remove smog equipment and tools needed...its the article i used to remove mine...

http://www.allfordmustangs.com//techarticles/Smog2.pdf