Fuel gauge up and down

My fuel gauge reads correctly, but every so often, it will fall to empty and then the low fuel light will come on. Shortly after, it will rise back up to the correct reading, and back down to Empty again. Could this be a bad sending unit? If not what could be the fix for this. Dont really mind it if the low fuel light wouldnt glow in my face all the time. Thanks in advance.

You called it - it's the seding unit, man...and unfortunately it isn't cheap. My 99 Envoy had the same problem, but it only started doing it when the fuel level dropped below half a tank. I just ignored it until I sold the vehicle a couple months ago.

You could try to run a couple of bottles of fuel system treatment through the tank, sometimes that works if the sensor is just fouled up a little. Other than that, you're looking at anywhere from $150-$300 for the part depending on where you get it, plus installation. Good luck though, hope that helps.

add a bottle of that concentrated techron in to your fuel.

I had the same thing happen on mine, the Chevy dealership near me charges around 900 to fix it, thankfully my husband got the part and did it himself which saved us around 600 bucks, but since its been fixed the gauge has been fine.

Just finished replacing the fuel pump/sending unit in my 01 Yukon. Inspection of the copper leads that pivot with the tank float revealed one of the leads was broken/corroded away, causing the fluctuation in the fuel level. The replacement (ordered from Autozone.com) was Made in Mexico, cost $330.00, and required replacing the stock connector with the one included with the part. wouldn't recommend going that way again. Instead, go to Rockauto.com, and order your OEM pump/sender from them.
Labor wasn't too hard, but ensure your fuel tank is near empty when you begin this project. Mine wasn't, and it can get pretty heavy and unstable.

Good luck!

This happens to me too, however because I own a 97' Hoe I don't even have a gas tank. And because for some reason the fuel tank is at some odd place the dealership was quoting me $1000.00 plus to fix it. So basically I just ignore it, although it does get kind of sketchy when I actually do have a low tank and it says empty, I don't know whether to take it seriously or not, but I havent gotten stuck yet, so I just live with it.

Fuel sensor/sending unit issues

I'm having the same issue w/my '05 Denali. I recently hit 50k miles and was hoping not having to come out of my pocket acct. the warranty. I'm gonna try some fuel additive first. But I'm open to add'l suggestions.

tippinon24s said:

My fuel gauge reads correctly, but every so often, it will fall to empty and then the low fuel light will come on. Shortly after, it will rise back up to the correct reading, and back down to Empty again. Could this be a bad sending unit? If not what could be the fix for this. Dont really mind it if the low fuel light wouldnt glow in my face all the time. Thanks in advance.

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I had to replace the sending unit, which I just replaced the unit, pump and all. Its working flawlessly now.

2 choices I see:

Do the work yourself; More headache if your'e not mechanically inclined.

Cash in on the warranty; given the semi-complexity of this job (drain fuel, drop the tank, remove sending unit, replace sending unit, replace tank) I think the warranty will pay for itself. It's the option I'd go with, if I still had a warranty!