Service Engine Light - Please Help!!

[lrwjr1964]

Hi all. Maybe someone can help me. This is the situation I am experiencing. I noiticed the X was bogging down slightly with rough idle. After a little bit of driving the SEL comes on. Go to Advance Auto and they pull the code and say it's my O2 sensor. They reset and the light stays off for about 3 weeks and the X is running better. 3 weeks later it comes back on with the same symtoms, bogging down, rough idle. Go back to Advance Auto and it's the same code. They reset. It stays off for a month and the X is running good. Now it comes on for a third time, same symptoms again. I figure it's for the same thing. I take the X to work and when I get back in and start her up 6 hours later, waddaya know, the Service engine light goes right off and the X is running good. It stays off for another 3 weeks, the X felt like she was missing badly and it came on this past Wednesday, I went to the store came back home and Wednesday morning when I started her up the service engine light did not come on. Now I will say that each time before the light comes on the X starts to act up like sluggish performance, rough ide. My question is, when the service engine light comes on shouldn't it stay on until the problem is fixed or the computer is reset? Why does mine keep going out? mind you also that when the light goes out the X runs fine. As of today the X is running rough so I am expecting the SEL to come on anyday now. Has anyone else experienced this? And yes i changed the IAC, cleaned the MAF, clean air filter. Can anyone shed some light on this?

 

[Cobraguy]

You have given us a fantastic write up and explanation...that we can't help you with because you omitted one little detail...what was the code????

I trust Autozone about as far as I can throw them. In many cases, an "O2 sensor" code is NOT an O2 sensor failure.

 

[lrwjr1964]

I don't remember what the code was but i do know they said Sensor 1 bank 2. The thing i don't understand is how does the service engine light go out by itself. I had a 95 explorer and when the check engine light came on the only way to get it to go out was to have it reset or un hook the battery. I did neither on this 02 X, but the service engine light just went off on it's own. Are the 3rd gen computers programmed to do a soft reset itself if the range of what ever made it trip the first time goes back within limits? I am totally lost.

 

[budwich]

cel light "function" isn't the same for all codes... that is, some codes set a "permanent condition" while others have a number of starts cycles, etc. If you search thru info on CEL or check engine light and obd, I think you will find some definitions that will help you understand why your light is going out "by itself".... Of course, it will always help to have the actual code as there are a "few" in each category for various components / conditions.

 

[Cobraguy]

Sensor 1 Bank 2 is the upstream sensor (the first one) on the driver's side.

WAIT! What the hell?? Is this on your 95?? It's OBDI and only has one sensor per side. This doesn't sound right. There is no upstream/downstream designation. Maybe their scanner designates it that way. Again, Autozone...so who knows. Maybe your ABS sensor is bad... (I shouldn't be so nasty to Autozone I guess)

There are many issues that will only turn the light on when the problem exists and the PCM finds a sensor, actuator, etc outside it's programmed limits. When it falls back to specs, the light goes out...but the code SHOULD still be stored in memory in the PCM for quite some time, or until power is removed from the PCM, or the code is manually cleared.

 

[KPT]

WAIT! What the hell?? Is this on your 95?? It's OBDI and only has one sensor per side. This doesn't sound right. There is no upstream/downstream designation. Maybe their scanner designates it that way. Again, Autozone...so who knows. Maybe your ABS sensor is bad... (I shouldn't be so nasty to Autozone I guess)

He said this was on his 02. Most parts stores aren't competent enough to pull OBDI codes. They'll plug the OBDII reader in and scratch their heads when it doesn't work.

 

[Joe Dirt]

What '02? I thought it was an O2 code on his '95?

I would go have them read again, and get the code numbers, then run back here...

 

[KPT]

What '02? I thought it was an O2 code on his '95?

I had a 95 explorer and when the check engine light came on the only way to get it to go out was to have it reset or un hook the battery. I did neither on this 02 X, but the service engine light just went off on it's own.

 

[Cobraguy]

Oh well hell! If I could read it would help!

Can I blame it on the OP for not making it prominent in his first post???

Still need the code though...

 

[lrwjr1964]

Sorry for any confusions. I HAD a 95. I sold her and now I have a 02'. Well it is now Dec 17. Last Wednesday Dec 10, once again the X started to run like crap more and more and I was just waiting for the SEL to come on again and low and behold it did. One thing I have noticed is that the X is really sluggish and the tranny starts shifting slightly harder when the SEL comes on. Well anyway, I went out to go to work the next day, start her up, SEL goes right out and has been out as of today and the X is running smooth. I think I am going to have to bite the bullet and take her to the stealership to have a full diagnostic run. I don't think I have a choice at this point. does anyone know indepth about O2 sensors? Everytime i have a code read it says O2 sensor. Can an O2 sensor start to go bad or once it goes bad it goes all the way? Secondly how many codes are there for a bad O2 sensor? By that i mean is there a code if lets say the electrical connector is bad as opposed to a problem with the sensor itself?

 

[Cobraguy]

Codes rarely, if ever, tell you what's bad. They simply tell you what's going on and it's up to you or the tech to figure it out. That can be very daunting at times. O2 sensor codes can be caused by engine problems, electronic problems, or just tired old sensors. You might run by an Autozone and see if they will give you the actual code number(s). We can help you from there. There are four sensors...but we should only be interested in two in this case...the upstream sensors.