Check engine light, can it be bad gas?

I have a 2003 Mercury Sable, which I was told is the same as the Taurus. I filled up with gas yesterday and my check engine light came on. I removed the gas cap and put it back on several times. Could this be bad gas causing this, maybe bad additives? What should I do let this tank run pretty low then fill up again or is there something I can add to the fuel I have now?
We now have two cars with check engine light, other is also Mercury 1997
Thanks

Take both cars to auto zone and have them scanned for codes and post the codes here. Auto zone will do the scans for free.


I have a 2003 Mercury Sable, which I was told is the same as the Taurus. I filled up with gas yesterday and my check engine light came on. I removed the gas cap and put it back on several times. Could this be bad gas causing this, maybe bad additives? What should I do let this tank run pretty low then fill up again or is there something I can add to the fuel I have now?
We now have two cars with check engine light, other is also Mercury 1997
Thanks

Hmm... that sounds very much like what I experienced weeks ago - look at this (http://www.automotiveforums.com/vbulletin/showthread.php?t=580071) thread. If you read through you'll see that my Service Engine Soon light went out on its own after a week or so.

By the way, a general question: what exactly is "bad gas"? Containing water or other contaminants?

By the way, a general question: what exactly is "bad gas"? Containing water or other contaminants?


Yes, however it is never a good idea to try and just guess what can cause a CEL. A CEL means one of a few hundred diagnostic codes has just been stored in the ECU (car's computer). Each code refers to a specific issue, but can be triggered by a few different things. So basically, it is a bad idea to jump to conclusions with a Check Engine Light, because it could be one of a thousand or so things.

As recommended above, take it to Autozone, they will be able to do any 96+ car for free. I do however recommend writing down every code they pull and coming back on here and doing a search. The people at autozone are great, and I appreciate the free service, but sometimes they aren't the most experienced people and hypothesize a bit too much (just speaking from my own experience) it's either a hit or miss with the people that work there. So it's always best to write down the codes, adn double check any suggestions they offer, before ordering new parts through them.

Doubt if anyone is following this thread, but if they are just a follow up.
The light went out. Guess it was the gas because the light came on right after I filled up

When you fill your gas tank, do you turn your car off or leave it running??? There have been instances, though rare, of liquid being drawn into the evap system during fillups with the car running, especially more so if you top-off the tank,, a lot of stations with newer equipment have posted signs advising against absolute topping-off, though I don't think it's for the reason above.. I think if anyone looks into this, there would be several Ford models and certain engine combos that may be susceptible.. speaking for myself, I always turn the car off no matter the weather, it's just something I've always done..

More than likely it was caused by refueling with the car running ... I'm waiting for it to happen to me. I have had bad gas - I bought gas right after they filled the inground tanks - and I had worse pinging and random misfires.

No the car was not running, I always turn it off when filling up.

Karen, do as suggested in a previous post and have the codes read at an auto parts house and post the EXACT code numbers back here and we can let you know what caused tha problem. The PCM has not seen the same failure for a few drive cycles and that is why the light went out. However the code is still stored in memory and can be retrieved.

Topping of the gas tank will kick the code too.The evap system needs space to breathe around.Do not top off a gas tank in an obdII vehicle.I know about this,my father knows a Vetronix rep that helps my father with car computer headaches that knows about this and has said something about this.