Fuel gauge not reading correctly

[edogg27]

Latley my fuel gauge will say i have more gas than i do then it will go way back down and up again while im driving. Its usually when i first start the car it goes up. Its been doing this since my alternator died and i got a new one but still the same issue. Any ideas?

[m0nkeyprince]

any codes?
mine did that when my charcoal canister leaked charcoal bits and clogged up the purge valve, but i doubt thats your problem.

for now, i recommend going from cheap to expesnive options, with the cheap option now being putting a bottle of techron fuel injector cleaner into your gas tank before a fill up, it can clear sticky gauges. get the one that treats 21 gals not 16 gals. available at any chevron

[Towncivilian]

I second the Techron suggestion. Use the larger (I believe 20oz.) bottle size, and run two tanks with it back-to-back. Techron has been known to fix sticky/misreading/nonfunctional fuel gauges. It's best to leave the car to sit a few weeks with Techron in the tank since the PEA detergents in it work better when they have time to sit.

[edogg27]

I usually use cheveron and i used it last Month actually but ill try again.

[Towncivilian]

If a couple runs of Techron in the tank don't help, you can measure the resistance of the fuel level sensor unit to see if it's faulty. See page EL-134 for details.

[edogg27]

I did 2 runs of chevron and it still isn't working. I guess the next step is checking the resistance level.

[edogg27]

So just an update it's still not reading correctly I've don't the gas cap and the fuel sending unit. I do have the canister purge valve code on but it comes and goes. Mechanic told me to wait a few months without topping off and let the gas in their evaporate. Idk if that will work or if I should just replace it. And idk if that will fix the fuel gauge. Any ideas? Thanks

[Towncivilian]

I don't think the charcoal canister would have any affect on the gas gauge operation. Since you've replaced both the gas cap and the fuel sending unit, perhaps the gas gauge in the instrument cluster is faulty? I wouldn't know how to go about testing this, though, unless you manage to find another '03 cluster at a junkyard.

[edogg27]

Thats what i was told but there so expensive and the milage wouldnt be correct.

[JustAboutFedUp]

Hello everyone my 03 Nissan Pathfinder LE gas gauge hasn't read correctly since I got the vehicle. Just thought I'd let u all know I finally got it fixed and reading correctly. If u take the cluster apart to where the circuit board is accessible there are 4 resistors I believe it was R97 R98 R99 and R100 that needed to b resoldered and that's what I did and it seemed to b doing much better but was still floating a bit. So I took back apart and just resoldered all of the resistors on the circuit board. Only took a few minutes and wallah works like a charm. I will post the video link that pointed me in the right direction. It's literally step by step very easy to follow.

[QX4ME]

Hello everyone my 03 Nissan Pathfinder LE gas gauge hasn't read correctly since I got the vehicle. Just thought I'd let u all know I finally got it fixed and reading correctly. If u take the cluster apart to where the circuit board is accessible there are 4 resistors I believe it was R97 R98 R99 and R100 that needed to b resoldered and that's what I did and it seemed to b doing much better but was still floating a bit. So I took back apart and just resoldered all of the resistors on the circuit board. Only took a few minutes and wallah works like a charm. I will post the video link that pointed me in the right direction. It's literally step by step very easy to follow.

I truly appreciate your detailed steps. Who knows I might need to do taht in the future. Just curious how did you find those four critical resistors for the issue? Are they in factory schematic diagram?