I have 7,500 miles on my 2006 6MT coupe and I live in Arizona. It is very hot here in the summer, so the windows are up and the air conditioning is on. Since I got the car in the Spring and took my time breaking it in, I never really heard anything odd noises until recently. Evening temps are finally low enough that I drive with the windows down and no A/C.

So, here's the deal. I first heard the knocking (or pinging) one cool evening. Since then I often suffer the high 90s or low 100s during the day to listen for the sound. It usually is heard at low revs in 1st and 2nd, and it seems more pronounced when the outside temp is high. I've tried 4 different gas stations with 1/2 tanks (only Chevron, Mobil, and Texaco, 91 octane). This did nothing. Took the car to Infiniti and the tech driving heard the sound and kept the car for the day. I got it back having been told "we reset the electronics," which I figured was the ECU. This too did nothing. In fact, I think the problem is getting worse. Any thoughts out there? Taking the car back in again next week.

P.S. Of course I've always changed the oil and done all the maintenance. After 6,000 miles I've gone only Mobil 1.

 

I would do a search. But it seems like alot of other have the same issue.

 

Thanks. A search told me that this is a problem had by many. Seems badly blended 91 octane gas and hot weather are the G35s worst nightmare, and I am lucky enough to have both of these things for 4-5 months a year.

I purchased NOS octane boost. They claim in raises octane on 16 gallons 6 points (and it says for off-road use only...if that actually means anything). After driving around for a couple of days with it in a fresh tank, the problem is lessened. NOT GONE, just not as apparent. The car actually seems to run smoother. Worth a shot for anyone with this problem. Just adds $10 to each fill up.

 

Are other's in your area having the same issue? In florida we have 93 octane, every once in while I get gas that doesn't work well with my car.