Check engine light

[Sanandreyas70]

Good morning,

Hoping someone can help me....

My check engine light came on a couple of days ago...i had Onstar run a diagnostic check and they told me that it was a minor emissions problem and could be either my fuel cap was not tightly sealed or bad gas. I was told to drive it about 7x and if the light did not reset to take it in to a Pontiac dealer. The light did go off that same day. I have since refilled my tank with gas and made sure my fuel cap was on tightly, but my check engine light has come back on.

I will probably take it in today to have it looked at if the light does not go off. Has anyone experienced this problem with their car? Any suggestions as to what i can do to fix this problem?

Thanks for listening,
Sandra

[gr8lover]

One thing that it may be is that the gas cap could be bad. Yuo cant see it if it is bad, but it will do that to your car. This is a problem that even brand new cars experience some times--- I would buy a couple dollar gas cap and run it for a bit and it should go away- good luck

[g8owneronthefence]

I just joined this forum after trying to find if anyone else had issues with a check engine light on their G8. It seems like a good place to share thoughts about my G8 experience. I bought my sport red G8 GT last May. I honestly can say it fit exactly what I was looking for in car, after driving a poor handling four banger for over 10 years. Big, fast and good looking, that is what I was looking for. It was great driving in the beginning but after awhile a few things began to bother me about the car, like 1) the quiet engine 2) the quick upshifts and slow downshifts, 3) the wind/road noise 4) the active fuel management vibration, 5) the suspension recall which I don't think ever fixed problem, 6) a squeak from the steering column when below freezing, 7) the occassional sulfur smells when accelerating and 8) a tapping sound from exhaust when heating up. But even despite all of these, I was overall still satisfied with the car until the check engine light came on a few months ago after 20K+ miles. It came on when I brought to car wash for the one and only time (always clean it myself). When the car came out of the wash it was on then a few days later it went off only to come back on a couple of days later. Since then it's been following the same pattern. Well the other day I finally brought it into the dealer (I wanted to bring it in when it was on so that's why I waited so long) and after taking the whole day trying to locate the problem, they couldn't find anything. They said it's likely an internal engine problem and they want me to take it to their other dealer which has better engine technicians. I don't get it??? For the most part I baby it and I'm averaging 22.2 mpg over the last 2K miles in mostly highway, but a lot of stop and go rush hour traffic. I can't really find anyone else on the web complaining about this issue or too much of the others I mentioned above.

Now I'm strongly considering trading it in for my first foreign make. Does anyone have any helpful thoughts for me?

[SalineG8]

These check engine posts are in the mechanical problems section but may better be described as and the result of computer problems. I have been experiencing check engine notifications on my '09 G8 which currently has about 5,000 miles on it. The check engine indicator was accompanied by reduced engine power. The first visit to the dealership resulted in no action because the code was identified but could not be replicated and everything was operating normally. After another week or so the ck engine light (complete with lightening rod symbol) was on again and the engine was running very roughly. This visit the tech tells me the main computer processor for the vehicle is faulty and has to be replaced. Hopefully this fix will take care of the problem for good.

[cracks666]

hey guys my check engine light came on after fitting a complete headers,racing cats,twin three inch exhaust on my ss-v commodore (g8) but i knew some one in the servicing department and he hooked up the laptop to it and found a faulty code due to the o2 sensors. the problem was due to the hiflow cat converters and the car thinking there was none there.a simple turn off the offending code and bingo no more light on the dash. still shows up on a full diagnostic check just not on the dash, and the car runs fine no problems at all

[lancewlaskowski]

i've got a 2008 gt and 2 separate occasions the check engine light came on and both times it was for a faulty fuel cap

[GScott]

I purchased my G8 GT July of 09. Within a few months I installed a Jegs cold air system shortly after that I experienced the CEL syndrome. Worried I called the dealer, told him my problem, the mechanic to whom I spoke to told me that the new air system I installed was the culprit due to the fact that these filters have a coating of oil on them and that it was fouling the maf sensor. I did'nt by that. It then went out, only to return a while later... I removed the filter cycled the ignition to see if it would cancel the CEL, and it did. I reinstalled the filter... no proplems. I then purchased a Power Booster chip . It installs in line at the accellerator connection ( a worthy investment,it diffinetlly increases the fun factor in the driving and performance, it also eliminates that nagging lag in the DBW ) Again with the CEL syndrome. I disconnact the chip, cycle the ignition waalla no light. I put back the chip... no problem. ITS THE FREAKIN GAS CAP! It loosens how or why I don't know. But every once in a while it comes on. I just tighten it up and within a mile or two the light goes out. Other than having to had the radio replaced twice and a tech recall on balljoints I'm happy to say that I'm prett satisfied with my G8. Suspension mods are in the works some racy gauges ( I like to know whats going on) a set of TSW Thruxtons on the corners...I'm good.

[joeyjing]

I had the same problem with my 2009 G8, the check engine light came on and all i did was make sure that when i put my cap back on let it go 2 clicks, never had a problen since over a year, hope that helps