Gas cap light... serviced 6 times

[MaudetheMalibu]

I have a 2009 Malibu LT and the 2.4L Eco tech engine. It has 4600 miles on it and it keeps having the same reoccurring problem beginning at a little under 2000 miles. I have now had it in the shop 6 times including dropping it off at the shop today.

This is the problem: When I fill up and let my car sit overnight the check gas light comes on after having 2-3 miles on the tank. It doesn't happen if i continue to drive it right away. When i fill up at the station the tank shows full but when i get to my car in the morning it says that it is at 7/8 tank, after driving less than 0.9 miles home from the gas station. This light only stays on for a few miles and then it clears itself. This has happened probably ten or more times. This morning like always the gas cap light came on with a little over 2 miles on the tank. Today on my way home from work not only did the check gas cap light come on so did the check engine light for the first time. The check gas cap light cleared itself but the check engine light did not and it ended up at the dealership. This mid day occurrence of the check gas cap light was only the second time it has gone off more than once in a day.

I have taken it into the dealership for now what is the 6th time (it is there right now.) And they have done the following:

Time # 1 run diagnostics and fog the system; no leaks found
Time # 2 run diagnostics and fog the system; no leaks found
Time # 3 run diagnostics and fog the system and replaced gas cap for a pinhole leak
Time # 4 drop the gas tank and readjust the lever arm
Time # 5 drop the gas tank and replace the sensor
Time # 6 ?

Every time they give it back they keep it for an extra night to check and this problem doesn't happen before they give it back. When i get it back i top it off and let it sit over night and it happens exactly the way it always does. The dealership has replicated the problem multiple times when the car is in their possession.

So now according to Nebraska law my car is technically a lemon, i have filed a complaint with the BBB and GM we are trying to work this out. So far all GM has done is offer me a free year of oil changes and tire rotation on a car that they cannot fix. The dealership has done all they can do and from the last time and here out they just have to follow the guidance from GM over the phone.

Has anyone else had this problem? If so what did they do?

[cavalier2000]

edit: you have to force them to fix the issue. one way or another. with under 5k miles i would just ask the dealership to switch you cars

[MaudetheMalibu]

Update... the dealership called today and said GM wants them to replace the entire gas tank we will see how that goes. They said Maude may have a hairline crack in the tank, but they have never had that on a new car.

[TMoneyR523]

If it comes on again scream "FACK YOU" (replace it with the real word) and it'll turn off.

That's what a Masshole with road rage would do!

[ATMofMN]

Where you park it overnight, is it on an incline? My driveway has a slight incline and the fuel gauge will show more or less than actual depending on whether I pull straight in or back in.

ATM

[BillD64]

It really isn't a major issue. At the worst you may be adding some additional gasoline vapors to the atmosphere. There are a number of places in the evaporative emissions system where a leak could occur. Years ago we just let the tanks vent into the atmosphere. Depending on how you top off the tank you may be getting enough gas into the tank that the expansion space at the top of the tank isn't large enough to handle the fluid's expansion thus causing a leak. What happens if you don't top off the tank?

Bill

[MaudetheMalibu]

As for parking it after it is filled up, it has been on a flat surface and it has also been on a slight incline, either way it goes off and the gas gauge drops.

The last time the gas light went off during the day and the check engine light came on as well. When the check engine light goes on my remote start doesn't work. My problem is it's a new car it should work. Someday down the road i'm not going to be able to sell my car because no one is going to buy it if i say "don't worry the gas light and check engine light, it might come on but it's been doing it since 1,960 miles."

[Macleod52]

When you top it off do you fill it up until the gas pump clicks, or do you keep pumping more and more gas in after it's clicked? If you're doing the latter STOP! That may be the problem.

[beach]

I had almost essentially the EXACT same problem with my ex '08 Pontiac G6 GT coupe, starting the very first morning I had it, the day after picking it up. I drove a mile after it sat overnight and ding-ding-ding "Check Gas Cap" came up on the DIC. I thought it was just a randomly loose gas cap that time, but it eventually turned into 3 months of it happening every week, usually a full day or two after I filled up over the weekend and had then driven to work and back once, and in a few occasions I also had the smell of gas in the car--that was rare, however.

Mine, in total, occurred 17 times in 3 months and it was into the dealer either 3 or 4 times for it, along with a couple of other things that were ongoing. They tested it, it was okay, tested again, okay...kept happening and eventually I filed a BBB Autoline claim, started that process with GM, etc. requesting either a fix or an equivalent replacement, and eventually the "final repair attempt" was scheduled. Dropped the tank, replaced the sending unit & fuel pump, did more checking, and gave it back to me 3 days later. Ran just as it had before, and within a day or two the "Check Gas Cap" alert was back, along with a newly fluctuating gas gauge up and down randomly, and the Check Engine light randomly a few days later. From the start I videotaped & uploaded everything, sending it to my GM rep along with the other dealer, etc. docs, and always did an Onstar diagnostics call when it would come on, and a week after the repair when I confirmed it not only didn't work but things were worse, I was offered the trade buyback just as I had requested. In came then my '09 Malibu 2LT, now also gone for other reasons.

So, yeah, I've had the issue and with the same platform/family of cars, but rather the 3.5L and a G6. At the time my dealer actually told me they had one case a couple of years earlier with a lady's G6 and the same Check Engine light, and after a few unsuccessful attempts, GM said to swap out the sending unit and such--which fixed it. Didn't for mine, and only resulted in more problems. Still have no idea what might have been the problem as the car was repurchased, sent through the GM process and then resold at a dealer...but I continue to wonder. It was truly bizarre.

[Trend1]

This would drive me crazy as well! I know this might sound stupid but are you using the same brand gas and gas station?