Hey guys, got a couple questions. 1) I went to AUTOZONE for them to check out my codes because of "CHECK ENGINE" light came on. He said it could be a multible things wrong (only 2 codes) he said 1 is the rear O2 senser or a TON of other things, 2nd code said the fuel cap and a ton of other things..... How does a fuel cap go bad? Also, He said that them are the 2 things he would replace FIRST!... FIRST, How many parts did he want me to buy until the light went out? He was telling me to go down the list of possibilities, Is there something or someone that could narrow it down? DAMN I dont mind spending some money for repairs, but to start replacing UNTIL the light goes off is just plain old stupid if all the first parts were good! My car runs great, its just the light is buggin me.so, Gas cap, Do they go bad? How do you check it (I know it sounds stupid), and the o2 senser is about $70 for the part, I will spend the $ if thats the problem, anyway to check it first? 3rd) I allready told my story about my rear window BLOWING UP from the "rear defroster ???" NOW I had a NEW window installed ($285 later) and the wire for the defroster is "scortched" a bit and Im terrified to hook up the defroster again. Not sure how to go about checking the wiring to make sure it doesnt blow again. Is there a relay that could have stuck and kept the defroster running? ( till it got SO hot the window blew up)any ideas? thanks a ton in advance......Michael..

 

the gas cap idk,i mean after use it could get to the point where it wont seal anymore and is not causing a lock,but like i said i have no clue about it

and for the o2,change it,but when you do you should change the upper and lower ones,and dont wait to,i waited and had a MAF and CAT go bad :/ so it ended up costing me around 700 and not the 100 something for both o2's

 

I had a check engine code on my '07 about 8 months ago, the code read something akin to tighten gas cap/too much air in gas/something blah blah, and an "engine running too lean" code. these happened at the exact same time.

well I pulled the cap off and the little rubber seal was worn and nasty, so I bought one for 12 dollars and stuck it on there. Drove it 30 miles to work and the codes both cleared themselves. So, yes it is possible for gas caps to go bad, even the guys at auto-zone said they have noticed they sell mre gas caps for chevys these days.

Fortunately it really is like 12 dollars, if thats not the issue you arent out much.

 

The actual gas cap code is more of an environmentally friendly code rather than an engine performance code. IIRC the code reads Evaporative System Leak (large) or at least something along those lines. 90% of the time, the gas cap wasn't screwed down all of the way which causes a poor seal. The other 10% of the time, there is actual damage to the evaporation system. Your best bet is to purchase a new cap. The o2 sensor is necessary to maintain the proper a/f ratio in your car. You could save a little money and purchase the universal sensor, you would just have to wire it yourself. As for the rear defroster.... Your story scared the poop out of me and there is NO WAY I would hook it up without being 100% sure on what caused the damage in the first place. Good luck!

 

As mentioned before buy a new fuel cap.

As for the o2 sensors, key thing is to replace both at once, since you don't want to go through the hassle of replacing one, then having to get the other replace a few months down the road.

As far as the defroster that's a tough call, i wouldn't want to risk anything, but i am no electrician.

 

What were the ACTUAL codes thrown? I don't care what the AutoZone guy said the codes meant, what was the numbers?

 

I agree with Chibi, get some codes posted. I really don't like AutoZone and their data is such a wide spread...
The gas cap can go bad, it does in fact have a seal to keep the vapors in (I have a car that the cap failed the emmissions pressure test). My wife's '01 Mustang threw an evap code (common cause was a loose cap or failed cap). I found the cause was thanks to Ford wrapping the filler neck in wireloom, it had rotted a series of pin holes (with that wire loom on, it protected it enough to avoid any serious gas leaks when filling). I did not like the cost of a new filler neck, so I cleaned it up and for POR15 and JB Weld, never saw the code again.

Now the O2 code, the rear O2 can in fact fail (our '05 Impala we just got had a failed rear O2). But that is also used to monitor the health of the cat. I honestly changed the rear O2 on the Impala because it was cheaper then a cat and I felt most likely the cause (code disappeared on it's own and the car passed it's emmissions check about 1-2 weeks later).

Post the codes and I'm sure all stories aside, better info can be shared.

 

do what millermontess said first. make sure your gas cap is on the right way and on tight. one time i didnt tighten it all the way down and i threw an evap canister code or something. didn't figure out my cap wasnt on till i filled it up with gas again.

 

Ok guys, Im gonna try everything you guys suggested. I have 2 Monte SSs and will take the gas cap off the other one and swap them and see if that code goes away. THEN I am going to post the aucual codes tomorrow so you all will know what they are, maybe one of you can decipher them better than AutoZone Guy (He did have a nice red shirt on though, so he did look like he knew what he was doing, cuz they were ALL dressed alike.....) and I think I will just replace both O2 sensers just in case, like you said, in pairs and not to expensive. Because that light is just bugging me BIG time. (OHHHH BTW Im gonna post a COOL Idea I did to my DASH (lighting) that only costs $5 bucks to change them to ANY COLOR you want...had to say that before I forgot .) So, change the cap, change the O2s and post the codes, or should I post the codes and then the O2s? I think Ill do that... may save a buck or 2. Thanks, Michael...

 

yea ur not alone. its been happening every time i reset the code. someone at autozone explained that its the ethanol in the fuel that keeps back the cap off and letting air into the tank or something of that nature. im getting ready to put a duct tape over the light and shrug my shoulder