Okay I'm a new owner of a 2008 g35x and I've had it for 2 months now with a couple issues and 1 was resolved by dealer warranty.
Ended up replacing my ecu. I Love this car btw!
My spedometer is off by 7%. I've searched the forums but couldn't find anything related to stock rims and tires like mine have. I've called dealership and it's been a week now and no answer. I'm going to assume that my milage is also off by 7% (higher)
I drive at 100kph on the spedo and 2 of my gps reads 93kph ( I live in Canada hence the kph) There are no recalls of such a problem but I would think that an expensive car like this would read the correct speed. Any advise as to correct this problem if the dealership decides not to fix it? Car still has factory warranty.

 

Hmm, did you have this problem before the dealer replaced the ecu?
Regardless, you're not alone with this symptom; lots of people seem to have similar experiences (strangely, most seem to be in Canada too ). If you search here you'll find numerous threads discussing speedo error. There definitely variation within the speedos, but tire diameter is an obvious factor too. If your tires are non-standard size, or even the correct size, but with a particularly extreme variation in tread thickness (too thick or too thin) it can add to the error factor. I'm not sure what the threshold is for a dealer to consider it excessive.

 

Rims and tires are stock. All have same tred wear... Bout 60% left. I know I can compensate the spedo error just by changing tires/rims but 7% is quite high IMO.
I thought motorcycles were bad at +-5% and at least i have the option to buy a spedo healer abd calibrate it my self but 7% for a $30+k car I would expect it to be bang on.
Plus the added km's on the odometer sucks for resale.

Idk I just called the dealer again and he will get back to me tomorrow. I'll post out the out come??
Meh..... So far an 02 sensor, a/f sensor bank 1, new cat right side, new tranny and an ecu. Got 8 months left of warranty so just trying to cross everything on the list off before it's up.

 

I'm having the same problem with my 2007 35X. I'm interested to see what the dealer says.

Keep us posted.

 

Dealer said there was a known issue for the 2007 g35 and the cluster was replaced to resolve the issue. Of course there is no recall but addressed with warranty. I'll let u know?

 

Is it just me, or has anyone else notice how many of those complaining of the issue are from Canada (or reporting kph instead of mph anyway)??

Is there a difference in our cars?

 

aren't all cars off +/- 10% legally on the spedo? I always laugh when people get tickets for 2 miles over, then nobody's spedo is that accurate.

 

This is the first car I've owned that's not bang on with gps.
To get any car pass inspection in ontario it states that the spedometer "has to be functional and in good working order"

Leaves alot of room for not being accurate.

 

well iv tested mine numerous times with many road radars, gps etc at various speeds and have always fallen within 1-2mph difference which is very normal for any car.

 

I completely agree being 1-2 mph off at various speeds is normal. In my case I'm 7% off at any speed. Big difference.

 

My Canadian 07 G35 Sport has the same problem. Stock sized tires and the speedo is off by about 7%. If I had the dealer swap the cluster, I wonder if they'll subtract 7% from the mileage. That would drop the mileage below what it was when I bought it lol.

 

^ they cant do that legally regardless of whether that would be the correct mileage or not, the interesting thing is that most canadian Gs seems to have the bigger difference while US side Gs have a much smaller difference in speeds

 

I was half kidding. Even if there was a way to do it I'm sure there's too much crap to go through, enough that it wouldn't be worth it.

But ya it's odd that it only occurs on Canadian cars, and I'm getting pretty pissed off that the previous owner didn't get any of these problems sorted out while the car was under warranty...my 07 is also plagued with the voice tag problem. Makes buying used a frustration, on an otherwise great car.

 

OK, good . . . I'm glad I'm not the only one seeing this.

SO, does anyone know if there is a difference in the build of the US model vs the Canadian model?

 

^ Wild guess here, could it be possible that the gauges weren't "printed" exact?