i have the same problem, it was like that when i bought the car though. ive learned to just set my trip milage. i get around 20mpg on a 20G tank so that should get me around 400 miles per tank. i fill up when it gets to 300.
but yea everytime i fill up it only goes like 3/4 the way up

 

I'm trying to remove the rear seat so I can clean my fuel sensors but can't release the seat retainers.

I'm looking at section SE of the service manual which describes how to release the seat and I don't see any reference to a plastic ring. There is a 'U' shaped wire loop that goes into a plastic retainer in the floor that has a hook that retains the wire loop. They say to lift and pull forward but I have done so with all my strength and cannot release the loop from the hook so I can pull the seat forward.
I must be doing something wrong but I can't imagine what.
Any help would be appreciated.

 

There are NO rings/pull tabs on the front of my rear seats and none are shown in the service manual regarding removal of the seat.

I'm about to lose my mind

 

try pull the ring then, pull the seat up.

 

i got a quote from my mechanic from INFINITI. He told me 100 for labor and 150 for the parts.

Good Deal ?

 

As I said earlier THERE IS/ARE NO RINGS UNDER MY SEATS. I went to my Dealer and he looked for them as well, and realizing there weren't any he then jerked the seat up with great force that I thought would break the retainers, but it worked and the seat came up and out.
I then removed the fuel level sensors, cleaned the potentiometer resistance element on the ceramic substrate, and then measured the resistance at both extremes, float in full and empty positions.
I noticed the readings were erratic and often way over what they should be which would lead to erratic and lower than actual fuel level indications.
I determined that the problem is not with the resistance element being dirty, but with the wiper actuated by the float making poor and intermittent contact with the resistance element. I disassembled the wiper assembly and bent the wiper arm to yield higher contact pressure and now the readings are what they should be and stable even when being flexed so as to try to create intermittancy.
I turned on the engine and the reading moved up almost 1/4 of a tank which is how much it was low. I'll fill the tank tomorrow, but I'm sure it will indicate full for the first time in years
I thought this would be of interest to others having the same symptom of the tank never indicating full and always reading too low. There may be other problems involving the dash instrument cluster or a high resistance connection in the harness, but I'd be willing to bet the problem with the tank sensors is the major problem.

 

Just filled up and for the very first time the needle went to the pin past Full!
I'm a happy G35Driver ;-)

 

anyone know if this is a good deal or not ?

 

Mine reads alright, but I do get it going back up a few times. Like the Light will come on then it will go away. I know how many miles I can go normaly so I don't worry much

though the DIY looks simple enough,but I don't see what exactly you clean.

 

[QUOTE=thescreensavers;5016445]Mine reads alright, but I do get it going back up a few times. Like the Light will come on then it will go away. I know how many miles I can go normaly so I don't worry much

though the DIY looks simple enough,but I don't see what exactly you clean.

/[QUOTE]
I wouldn't worry about the light as it will go on/off when at the trigger threshold. If your gauge reads OK then there's no need to do anything.
If it ain't broke don't fix it!

 

anyone know where i can find the DIY to clean the fuel sensor ?

edit* FOUND IT
http://www.nicoclub.com/FSM/G35/Coupe/2003/fl.pdf

BUT WHAT DO I CLEAN ?!? i see alot of stuff but dont know what part is needed to be cleaned ?!

EDIT* can anyone show me a personal DIY for this , these black and white pdf pics hurt my eyes lol

 

HELP PLEASE WITH THIS ^ i need to know which side (passenger or driver) i need to open and what part inside the senor i need to clean with a qtip, thanks

 

isn't there a TSB on this issue?

 

Look at post #85-87 by moses, on this threat. He took some really good pics on where and what to clean.

 

^ thanks... I didnt even know that was there... Im going to try this over the weekend.

So just bend the bar and clean something with a q tip... sounds about right?