Check Engine Light/Oxy Sensor (lots of detail in post)

Hi!

New guy here.  I have a 1998 V-6 A/T Camry with 95,000 miles.  Had the car for over 5 years with no problems.

Then my "check engine" light came on.  Took to a mechanic, put computer on it and he said my front oxy sensor (S1?) was bad -or- I had clogged injectors.

He recommended I rule out the injector issue by running a tank of premium through it and putting in a bottle of techron before buying a sensor.  He cleared the code and I drove it for a day .....and the light came back.  Thinking it may have been due to  not enough time to clear any problems I kept driving the car and put in a couple more tanks of gas to make sure.

For the record so that you know, I keep meticulous books on my car and jot down all purchases, track gas mileage between fill-ups, etc.  That way I can tell with certainty if I may be having a fuel filter problem, spark plug problems, injector problem, fuel/air mixture problem, etc. because they will result in altered gas mileage.  For years this car has given me between 23-24 MPG in town.  That still has not changed.  It still does.  Even with over 500 miles on it since this began.  The car starts right away, pulls aggressively, has plenty of power when I kick the accelerator.  Never misses.  Never stalls.  Never hesitates.  Runs like a bat out of hell.

Three weeks later the light was still on and I thought maybe it was one of those deals where once the light is on it stays on until you take it to a mechanic. (I didn't know about the disconnecting the battery thing.)   Anyway, back to the mechanic who cleared the code again and a day later it was back.  So I bought a new sensor and he installed it.

A day later the code was back...AGAIN!

Now I am a bit concerned.

Anyone have any ideas before I drop a couple more hundred dollars on the second front sensor (or the rear one) and installation?

I've got the identical problem, also replaced the same sensor.  I'd love an answer too!

Been back to my mechanic and he says he will contact his diagnostic group to find out if they know anything.

Spoke to a couple of people who said that they just ignored the light and nothing bad ever happened.  One person recommended pulling the bulb.

Ignoring the light is fine for me as I do not take long trips in the car but when I go to sell it, can you imagine trying to convince a prospective buyer by saying, "oh, that light?  Never mind.  It's nothing.  Trust me!"

Would YOU buy a car from someone with a check-engine light on?  Maybe for hundreds UNDER the blue-book......just in case.

All the more reason to get this fixed once and for all.

One more thing, if there are moderators on this forum who think I should post this elsewhere, please advise.

Its not uncommon for the check engine light (cel) to remain on once youve resolved the problem area. Usually the ecu will correct itself and the light will go off on its own. Or you reset it manually by unhooking the battery.
 
1st off stop running 93 octane. Put what youve been putting in it for the past couple of years. Changing brands may help. You dont have a corvette and your car doesnt require higher octane gas. If you want to clean the injectors get a fuel injector service done. Maybe some seafoam or even injector cleaners you can find at your local auto parts store. Running 93 could cause more problems in my opinion.
 
Id start by replacing the rest of the o2 sesnors getting a tune up...( your at 95k lets be honest its that time) new plugs wires and or coil packs ect. Replace all filters and fluids. Id be more than willing to bet you have a bad carbon build up problem. You seem like you baby the car which could be a bad thing ...if this is the case. A good 2 hr drive on the interstate would probably help out alot.

pulling the bulb in CA will do you more problem then fixing it. we gotta get our car smog ebery 2 years. and before you sell it you have to get it smog if not you then the buyer will. if the buyer was smart enough he will tell you to smog it which in term wont pass the visual test since the light wont come on when the key is on the on position with the engine off.

and yeah try running some seafoam. and letting it reset manually like 05 suggested. and beware if your gonna do seafoam it might or might leave a big white cloud of smoke...

BTW when i run 91 octane i get about 2 mpg difference.. lol

Hello all,
 
I've been following several threads on the CEL issue. I have a 1998 LE l4-2.2L with about 100k miles now. Done recommended service, t-belts, water pump, tranny services, etc. After taking a long trip (highway speed, 150 miles is long for me) and parking, returning later to come home the engine light came up.
 
Absolutely no driveability issues, noises, etc. The car seems to run as it did before the CEL.
 
Took it to a shop, and pulled the codes:
 
0125B - Insuff coolant temp, replaced thermostat reset CEL, problem returned 1 hour after picking the car up. Also had the fuel filter replaced too (not related, but due to be changed out).
 
They pulled additional codes:
 
P1133 - Air fuel ratio sensor circuit malfunction.
 
P1135 - Air fuel sensor heater circuit malfunction.
 
Technician swapped the sensor for a known good one, retested and the light came back up. They checked the other components (water temp, vacuum, etc) and suggested it may be a wiring problem. Quoted $90 bucks an hour to "look for the problem". Needless to say, I'm here for suggestions!
 
Also - I found a TSB related to this issue - TSB EG00999. Does anyone know any details of this bulletin (how to correct, locate, etc?).
 
Thanks in advance....
 
-G