Various issues on used 2006 g35x

[kbflip02]

so i just recently purchased a 2006 G35x with 88k for my wife and have been noticing a few things. First let me point out that the car was purchased from a private seller who i am no longer able to contact. One thing i noticed was a clicking or rattling which may be cv joints or wheel bearings and i will check that when i can get it on a lift this weekend. i also noticed when i filled it up (i only use 93 octane) and did the math i drove 321miles and put 19.7 gallons back into the tank. Considering it had mainly driven it on the highway and not had to stop and go at lights i was shocked to see i get less mpg than in my cammed out J.i have been a long time member but have not posted in forever since ive gotten married and had 2 kids since i joined years ago...i would like to know what i need to watch for as well as what i should do first as far as PM. saturday will make it a week owning the car and i plan on changing the oil and air filter...possibly the plugs...and more than likely getting some new tires bc the tires that came on the car are in bad shape...also when i press the vdc button nothing happens at all neither a light on the cluster or even a difference in driving...any info would be greatly appreciated....im not sure what could cause the gas gauge to be off and not the tach or thermostat...which makes me think what else is wrong....sorryy for ranting on the long post...

[joe603]

Here's a few things I would do...First, accurately calculate MPG using the odometer. Next, plug change and oil/air filter change is a great idea; it will only help. The fuel gauge could be a sending unit issue (seen it before).

I think you're on the right track for the clicking/rattling...probably wheel bearing.

Finally, the VDC button...I think you have to hold it for a few seconds (not 100% sure). Check out the FAQs/FSMs for the car (link in my sig) as you see fit. Good luck!

[RED_DET]

The VDC should illuminate on the gauge cluster as soon as you push the button. This notifies you that the VDC is somewhat disabled, but can't be completely disabled. It may just be the light doesn't work, the only true test is to start the car up, go for a drive, push the button once and see if you can get the car to break traction without the hinderance of the VDC. If you feel the car bog down or cut power during excessive wheel spin, the VDC is still active and pushing that button doesn't do anything....The VDC will flash on the gauge cluster as it begins to activate and gain control. So look for that as well.

[kmckis1029]

spark plugs on your car are at the end of their life (they last about 100k miles) if they haven't been changed already.

also you might what to change the front and rear differential fluids if that hasnt already been done in the 88k miles, its as easy as doing a oil change. (just with a horriable smell)

consider induction cleaning with base idle reset and/or running some fuel system cleaner after you have fresh plugs. (easy base idle reset is to leave battery unpluged and hit brakes a couple times)

then lastly id upgrade your transmission fluid to matic S, if the transmission fluid hasn't been changed within the 88k miles.

should be a nice boost in milage with fresh fluids, spark plugs, induction/fuel system cleaning/idle reset, and air filter replacement.