Is my fuel gauge horribly inaccurate or did my tank shrink?

[TowGMC]

Towing back from racing a week ago I pushed my limits and had the warnings on the Nav screen telling me I had 30, then 23, then 14 miles to empty. I'm sure if the Nav could talk it would have yelled at me.

But when I fueled up, it took just 22.1 gallons, not anywhere close to the 26 gallons the tank is supposed to hold? And the trip computer on the tach said I'd used 21.9 gal so it's pretty close to what I put in. So where's the other 4 gallons? I've never put more than 21.5 in before this, so wasn't too surprised but still, that's a lot of fuel reserve going to waste.

I'd just suck it up, but when not towing and I'm getting 18 - 19 mpg on the highway, that 4 missing gallons is another 72+ miles of driving time, or close to an hour.

Unfortunately the friends with Denalis all have XL's which have larger tanks so I can't compare with them.

 

[2007tahoe]

The fuel gauge on my 07 completely sucks. As soon as it gets to about 1/3 tank it gets very inaccurate. I will park on level ground over night with 1/4 tank and next morning I will be sitting on e with low fuel warnings for several miles then slowly go back to 1/4 tank. I am just going to wait until the pump goes out and replace the hole unit.

 

[BEEMDUB]

The fuel gauge on my 07 completely sucks. As soon as it gets to about 1/3 tank it gets very inaccurate. I will park on level ground over night with 1/4 tank and next morning I will be sitting on e with low fuel warnings for several miles then slowly go back to 1/4 tank. I am just going to wait until the pump goes out and replace the hole unit.

I know exactly what your talking about....Except my truck isn't level when it happens when I go to football workouts I park on a slight angle and my truck sometimes has been close to a 1/4 difference from where it was before I parked it, and on the way home it slowly rises.

 

[TheFuzz]

I've noticed the same thing on my 07 since buying it a few weeks ago. Had just over 1/4 tank when I parked it, but the next morning I thought for sure I had a fuel leak - tank was on E. Driving down the road toward the gas station, it slowly crept back up to normal.

Pretty sure my vent valve solenoid is toast though - I've got a P0446 CEL, and filling it up yesterday took about twice as long as normal because the pump kept cutting off. I wonder if that has something to do with it being so innaccurate once the tank gets low? I'll keep an eye on it once I get the solenoid replaced.

 

[604Escalade]

Silverado and Escalade both have done this. Their gauges are very inaccurate when it's not sitting on level ground.

 

[felixgun]

Back in 2010 I was on a roadtrip in my vehicle with 3 friends from LA to CO to go snowboarding. It was my buddies turn to drive since it was a 20+ hour road trip and sure enough I wake up and we are on the side of the road with no gas. The DIC said 36 miles until empty. COMPLETELY inaccurate. Don't trust it! If it gets anywhere near the E you might as well fill up.

 

[TowGMC]

Geez, those are the responses I hoped I wouldn't see but it at least tells me I'm not alone.

My dealer had replaced my fuel level sender for another problem back last December and I'd been thinking we got a bad sender. Apparently they're ALL bad.

I guess what irks me the most is that I don't know if I truly have 4 gallons left in the tank, or if the truck tank is actually just 22 gallons. But seriously, 4 missing gallons out of 26 is a 15% error factor. So did GM call it a 26 gal tank for marketing purposes or is their QC so horrible that they're being manufactured 15% out of spec?

Think next time I'm towing, I'll fill the fuel jugs in the trailer with 93 octane (they usually have 100) and drive it until it runs out of gas. At least I'll have fuel in the trailer to get me going again. I just think it's insane that this is what GM quality has caused us to do.

 

[pwtr02ss]

Its not that big of a deal to just fill it up when the gauge is close to E is it? Running a vehicle below a 1/4 tank over and over cause premature pump failure due to excessive heat. I don't know how accurate mine is, I only push it when I'm not close to a fuel station.

 

[TowGMC]

Its not that big of a deal to just fill it up when the gauge is close to E is it? Running a vehicle below a 1/4 tank over and over cause premature pump failure due to excessive heat. I don't know how accurate mine is, I only push it when I'm not close to a fuel station.

It is when the damn error results in an hour less driving time on the highway. Plus the fact that we don't know where E even is on these trucks now. When the distance between convenient gas stations on a 1000 mile trip is 50+ miles, the lost fuel capacity can be the difference between making the next exit or calling Onstar.
But the biggest pain in my mind is the fact that GM tells us we have a 26 gal capacity but nobody has any idea what the true capacity is, so everyone stops early to avoid problems. That's a complete and total lack of quality control.

Oh, and for 40 years and close to 900,000 miles I've run my cars down to E and have never experienced a fuel pump failure. As long as a pump has fuel in it, it's getting cooled properly. That used to be true in the days of the old mechanical pumps bolted to the side of an engine block, but today the only risk is running the tank dry and no fuel in the pump.

 

[GM Customer Service]

I've noticed the same thing on my 07 since buying it a few weeks ago. Had just over 1/4 tank when I parked it, but the next morning I thought for sure I had a fuel leak - tank was on E. Driving down the road toward the gas station, it slowly crept back up to normal.

Pretty sure my vent valve solenoid is toast though - I've got a P0446 CEL, and filling it up yesterday took about twice as long as normal because the pump kept cutting off. I wonder if that has something to do with it being so innaccurate once the tank gets low? I'll keep an eye on it once I get the solenoid replaced.

Hello TheFuzz,

Congrats on buying your 2007 Tahoe! I hope you are enjoying driving the vehicle around. Be sure to keep an eye out for any inaccuracy after your part replacement, and reach out to us if other concerns arise.

Regards,

Laura M.
GM Customer Service