I decided to trade in my 2000 Jetta GLX with 70k miles for an '05 G35 sedan 6MT. Wow, what an upgrade! I'm completely addicted to the car and always get a grin on my face when I'm behind the wheel. I do have a few concerns that I hope someone can address, or at least point me in the right direction.

1. The wheel wells are extremely loud when going over gravel/sand. I even need to pause a conversation with someone until the road is smooth again. Believe it or not, I can hear water hitting the wells (it's almost louder than the regular road noise).

2. If I shift after 4000 rpm, there's a loud growl coming from the exhaust area. Not sure if this is normal but I don't remember hearing it on the other 6MT's I test drove. The higher I go above 4000 rpm, the louder the growl.

3. My gas mileage is much lower than I expected. 17mpg on the first fill up and 15mpg on the last one. I definitely haven't pushed the car that much yet. Most of my driving is in the city with an average trip of 5-10 miles. I was expecting more like 19 mpg.

4. The brakes seem much softer than the ones I test drove. I remember the demos had fairly touchy brakes. I have to push quite hard, especially if there is someone else in the car.

Thanks for the help!

 

while you should be getting better gas mileage, I think your milage woes are similar to mine. when I first got my car two months ago, I didn't drive anywhere unless I was flooring it, i.e. constantly reving it upwards of 5k until I hit 80mph on average, and my milage suffrered for it. of course it was still a little warm here in so cal, so I was always doing this with the AC on, and I must say this cars mileage is really hammered with the AC (anyone else notice that?) so my first couple of fillups were turning out to be around 18.1-18.5 mpg, and only about 365 miles until the E light comes on. after I settled down from "knocking the carbon loose", I manage a more acceptable 21-22 avg milage and about 400 before the light comes on. just remember that that light comes on you have upwards of 4 gallons of gas, so you have plenty of time to get to a pump. once the newness wears off a little and you get a little more conservative on the pedal, your mileage should go up. now I rearly in normal driving go over 3500RPMs unless I'm passing a car up a hill on the freeway, so my mileage got better. seeing that you have the 6MT, you should get better mileage, but like I said tone that foot down, or you won't see it. even with my conservative foot, my 93' Ranger still gets better gasmileage, averaging 23mpg of couse it isn't worth the water to wash it, feels like it is going to fall apart, and can barely do 65mph, but hey its paid for, so I can pay for the G35. mappy motoring

ps my 21-22 is average per tank. my wife is the pprimary driver and does a lot of city driving, but we put on average 150 miles a week on the local freeways and the rest in stop n go traffic, and a lot of starting drive two miles and then turn the car off, and like I said I'm still averaging up to 22mph

 

Good luck with your ride! Most of what you're talking about is normal.

 

i'm close to 1200 mi. in an '06 5AT sedan so hopefully this info might help

1. no experience with this.

2. i've read that the sedan exhaust stays quieter at lower rpms and opens up to be louder at higher rpms... i definitely like this. also, if you follow the breakin period details, you shouldn't exceed 4000 rpms...

3. my first 4 tanks have all been under 18mpg and i was following the breakin pretty closely. i don't think this is unusual. many people have stated their mileage improved after a few thousand miles on the car.

4. my brakes seem fine, not too grabby.

 

I wish I could comment on what these cars put out on average new, but like I said mine is in the mid 40ks on the odometer, and its gas mileage is passable. its only .75 off from my old volvo, but it has twice the power, and the engine is 1.1L larger in displacement, so the tradeoff is worth it. maybe they fixed the brake sensitivity on the 06 models, my 03 stops pretty hard, but very satisfing, just drive something else its a MAJOR difference. your mileage will improve for sure, but prolly not until around 10k will you see it start to increase you may never see anything above 23mpg, and if you do good on you. but I'm one of those guys who will drive a car until its starts to sputter and if I'm averaging less than 18 that will hurt at the pumps, my second tank of gas out here in so cal was 19.1 gallons and it was over $60 to fill it, so for day to day driving I put in regular and keep the toes lite on the pedal. but once you get a couple quarts of oil ran through that engine, you are gonna have that kid on christmas expression on your face, I drive 1/2 mile to the corner store with a grin on my face, and I don't even go above 35 (when children are present) good luck with your new cars, gents.

 

Not sure about the gravel, but the water in the wells is normal.

Growl can mean a lot of things. The note on our cars is loud and pretty distinct - it shouldn't sound out of place, though.

City driving with short trips = crap mileage. 15-17 is not unusual. You'll do better on the highway. I noticed this car has a big diff in gas mileage (moreso than other cars I've owned) going from city to highway.

That's weird. The G35 has really good brakes. I'd bring it in and mention it.

 

1) I have not noticed this on my 05 6mt but I think it's normal. I have noticed it is very loud inside when it rains. In general, it's not a quiet car.

2) It sounds like you are talking about the exhaust note. It will of course be louder at higher rpm's. The 05 stock exhaust is more aggressive than the 03-04. If it doesn't sound right, have the dealer check it out.

3) 19 mpg is very optimistic for city driving. 15-17 is very normal for driving around the city whether you push it or not.

4) The 03-04 brakes were very grabby. The 05 should be smooth but not feel like you have to smash the pedal to stop. If you feel like the car is not stopping correctly, get it checked out at the dealer. There could easily be a problem with the brakes.

 

#1 can be impoved a lot with some sound dampening like B-quite or dynamat
LINK

 

I have a 2005 G35 6MT and I think I know what you are talking about when you describe the exhaust noise, although it aint coming from the exhaust. The noise and vibration you are referring to is the sound of the return springs on the clutch. I also found this to be a little bothersome, especially when the car was newer. It seems a little out of place in a luxury sedan, especially one from Infiniti. But i guess, thats the price you pay when you have 300hp running through the flywheel in a car that is designed to take all the abuse you can throw at it. As the RPM's climb, the noice gets louder and louder. One thing i did notice (as my last car was a Jetta as well - a 1.8T with over 215hp) is that the throttle is very sensitive and very often, i overrev the engine when i clutch, that will make the noise sound louder as well. BUT MAN O MAN DOES THIS CAR MOVE!!!!!!!!!!!!!!!!

I wouldnt worry too much as this is the second "05 i have driven with this noise.

Enjoy!!!!

 

1. Road Noise - Check the Road Noise thread, I believe in the G-Spot section. While the advice is intended for coupes, I believe that sedans will also benefit from adding insulation in the indicated "resonance chamber" behind the front wheel/fender liner.

 

I am really surprised no one responded correctly to the one question he had.

The noise you hear that gets louder is not the exhaust. You only hear it when you push in the clutch and its a ROAR noise. It's your clutch/flywheel spinning at high rpms when you release it. Then it spins down. It is a noisy flywheel on this car, but all the 6mts I have driven do this for the 05+ models.

The road noise is normal.

My gas mileage hasn't been lower than 19. 90% of the time it is 21~ mpg city driving. When I race at autox it only goes down to 19mpg. It has never seen less.

A lot has to do with your driving. The brakes will be better after you put a few k of miles on them.

 

Ditto what everybody said ... your car is great. If you bought this car for 5-10 mile city trips, it is gonna get dog mileage ... but who cares if you're only driving it 20 miles a day?

 

Funny, sounds alot like what i said before. Maybe if you would read the reply, you would have seen that i address that clutch noise issue.

Happy ROARing!

 

I have 6500 miles and I usually get ~20 mpg with combined city and hwy. Although the last few weeks the mpg has fallen off a bit because of winter driving and defroster usage. I also noticed that the G is very loud when driving in the rain, it sounds like pebbles hitting the roof, much louder than the Accord I used to have.

One other thing I noticed, now that I mostly drive with the windows up. I hear a low hum that goes up and down when accelerating and letting off the gas, any one else notice this noise?

 

As your finding out, this car doesn't get that great of gas mileage. While in theory the 6MT should get better gas mileage, I think the opposite is true that the AT gets better gas mileage. Reason being that the power delivery is so addictive that your tend to drive the 6mt more aggressively and the AT coasts more where you would have to give the MT gas to maintain speed. With my 6mt I get about 16-17 and if I baby it on the highway, about 23

The force reactive brake assist was recalibrated for '05. It's not as sensitive. I prefer the right now braking on my '03.5

Sound deadening equals weight if you're truly concerned you can install dynamat or have an undercoating like Ziebart sprayed on the chassis pan and wheel wells. The worst car for road noise I have ever driven is the Mitsubishi EVO 8 which has none. I could barely speak with my wife on the test drive.