This started a week ago... I noticed that my gas gauge started to show more that i figured was in the tank... In fact i could go across town 45min ride and the gas hand only move an inch.. lol Even the distance to empty is lying too b/c yesterday morning i started to work 15min away and it said i had 128 miles till empty, but when i got to work it said 168 miles till empty!! The gallons used and instant mpg and mpg seems to be working ok, but anyway, what could be the problem here? Im dropping it off at the dealership to be fixed next week.. But untill then i put 10 gallons in to make sure i don't run out by then..

Well, the distance to empty can and does go up with the AVG mpg, so if you started driving a little better it might go up that much. On the other hand, if the gas gauge isn't moving as much as usual, it could indicate a problem. The gauge on my SSEi has always been very accurate. The one on my SLE will be within an 1/8 of a tank. It goes up and down in that range.

GM replaced the Cluster on my GXP, when I had the same issue !!

I know that some PCM'* between 1992 and 1998 had an issue with an improper fuel sender calibration. GM issued a fix in the form of updated firmware.

I doubt they'd repeat the same mistake twice, but it may be worth trying to find out if the GXP'* have a similar computer issue.

i dont bother looking at the guage, it always seemed off for some reason, but good luck trying to convince GM with it lying, its "normal"

what i do is reset the "Fuel Used" everytime i fillup gas, and whenever i hit 62 litres i refill it (since the GXP tank takes 70 litres). usually my fillup is very close to the fuel used, about half a litre or 2 off max

I didn't think about using the fuel used to measure how much is left... derp.

Good tip Sam.

dont count on it the first time, see how off she is the first few times, my 03 grand prix was way off, almost 7 litres everytime i filled up, no idea why
but the GXP is way more accurate

I've apparently been blessed with a GREAT GXP as I've had so few problems with the car. I do, on the other hand, put a bottle of injection cleaner in the tank, and then a fresh fill-up about every 4 months. I'm sure that keeps my tank, float and sensors clean in the tank too. I never use off-brand gas and usually never let it get below a 1/4 tank, especially during the winter months. I'd try running a couple of quality bottles of injection cleaner through the car before you take it in. Just a thought.

yeah mine had been great too thank god.
funny how those cars were more like hit and miss, its either a great car, or no luck whatsoever

Yea, i haven't had any issues with my GXP either until this gas thingy... my car haven't seen any off brand fuel either and gets chevron fuel injector every 2 months. My fuel hand has been right on the money every time since i had it.... relying on the Gal used is what i been doing for the past 2 week, but If it wasn't under warranty sure i wouldn't mind doing that and not paying loads of money to fix it... So if the distance till empty is adding like 20-30 miles on a 15 mile trip to work; would a bad cluster make it do that too!!! Either way Thanks guys for the replies!! And i have an appointment tomorrow morning at the Local GMC dealership to drop it off so i'll keep you guys informed!!!