2007 CX9 AWD GT - Starting/Idle Issue
 

If this has been asked before I apologize feel free to direct me to an answer. My 2007 model has 110K on it and it was having issues starting in the morning and then it decided to at a low rpm when I'm at a stop almost to a stall. I thought maybe clogged fuel filter so took it into dealer service it was due for oil change anyway. I usually run regular gas from a reputable station (no off brands). No Check engine light. When I took it to the dealer for service, they told me it was showing a code that indicated a Gas tank vacuum issue but they had never seen that code before so were going to keep it and check with corporate the next day. The next day, according to the techs, it was not displaying a code and it was running fine. I know cars have a way of magically fixing themselves when taken to the shop much like children magically heal themselves when let home a day off school...but...

Has anyone heard of this? Thoughts, etc are appreciated.

I always put my gas cap back on until it clicks, and I never run it lower than 1/4 tank 90% of the time. It has been dealer serviced since I bought it and I am the original owner. I did have to get the internal wiring harness replaced a year ago as the car ran VERY rough suddenly and the check light came on - not surprised it had damage as I live in a hot state and for a while had to park outside in summer (but other than that the car has been garaged and garage parked while at work). I love my car, it's paid for, and I'd rather not get rid of it but a gas vacuum issue has me somewhat concerned. thanks for all responses. :)

If we knew the actual code it could help us figuring it out. Without it i feel like walking in the dark.
Also it is possible that the code has nothing to do with your rough and unstable idle. how old are your spark plugs and ignition coils?

Thanks for the feedback
 

Thank you. I did not get a code from them, they kept saying they never had seen it before and then when they ran the diagnostics again it didn't come up at all. And now the car is running fine. I'm going to run a couple of tanks of premium thru it and maybe it was just a weird situation. My husband said in the old carborator days when it got real hot out the gas used to literally evaporate and cause issues but shouldn't happen with injectors now but its been really, really hot here lately. Spark plugs, and coils and fuel filters are all fine. ???? Like the kid that wakes up, pukes, then goes and plays an hour of soccer. Sigh.