2021 Tahoe RST Abismal mileage

[revengejr]

Hi guys,
I bought a 21 Tahoe RST back in February. Before that I had an '18 Suburban and before that a '15 Tahoe. My wife likes a new truck every few years and drives primarily in suburbia as a school bus for our kids. Our driving habits have not changed however on this new Tahoe, we have been averaging about 8 mpg. It's advertised as 14 mpg city but were getting barely 1/2 of that. Anyone else experiencing a similar issue? We are at the pump almost weekly. It's a complete disappointment. I've had it in for servicing once under warranty already for an SRS light but they didn't note anything unusual. Any suggestions? Thanks for the help!

 

[1BADI5]

That 6.2 life YO!

 

[Goldenbear03]

That's extremely low and worth having looked into. My wife has somewhat of a lead foot and still managed mid-14's on her Escalade.

 

[MelloYello95]

A few months ago at the beginning of this chip shortage, I read several articles of GM leaving chips out of the fuel management system on the trucks. I hope they are not doing it with the SUVs. Would a company rightfully have to declare that to the consumer if that was the case? We have a 21 Yukon and averaged very well on our way home on the highways. Now that we've put about 2k miles on it around town, I'm averaging around 14-15mpg. That's about what my old one averaged. Make sure your not using anything below 87 octane.

 

[revengejr]

@1BADI5 It's a 5.3L not a 6.2. My suburban and older Tahoe had similar engines but we experienced much better mileage - about 15mpg. I don't think this truck has the AFM in it like older models. My old trucks would tell us when it was going from 8 cylinder to 4. I've also see the GM lawsuit about that issue on older models but from what I've read that only occurred after several thousand miles. This truck doesn't have that. We are at about 1,500 miles and about 160 hours on the engine. We keep in it in 2WD almost always and don't use any of the performance modes either. I've also noticed that cars computer reporting we are down to 50% of the oil life at only 1,500mi??? We are planning a 1,300 mi trip in June and will be towing about 4k lbs so I need to make sure everything is up to par. I will ask tomorrow about the AFM system. It's a good question.

 

[Goldenbear03]

I'm getting 16+ with my 5.3L AT4.

 

[Blueinterceptor]

That 6.2 life YO!

21 rst is 5.3. 6.2 only available on high country



what’s your highway mileage?

how much idling are you doing? That would impact your mileage.
If I sit idling(disable the auto stop) I get 9mpg

 

[Quark]

Having owned 2 other very similar models and assuming driving habits haven't changed it sure sounds like something is off . Hoping you get it resolved and let us know what was found.

I will bet that it will be a problem as it can be blamed on the owner and will be almost impossible to get their attention. If you need motivation to get this corrected remember GM's profit was $3 billion last quarter.

 

[revengejr]

Just got back from the dealer. The service advisor agreed that the mileage was low so they want to do a 1,000 mile test. Basically, come in, do an oil change, top off al fluids and then drive for 1,000 miles. Bring it back, they will check all of the levels, specifically the oil, and see if anything seems amiss. Then do it one more time at the next 1,000 miles and see if anything crops up. If nothing happens, then we concede terrible mileage. Not very promising especially since I am moving to Florida from NY in 5 weeks. They said this is a GM protocol and the dealer in FL should know what to do. Best part of it is we are driving from NY to FL, about 1,300 miles, so I can't even start the process until I get there, as GM requires it to be rechecked exactly at 1,000 miles. Yay! FML. I'll post on here in late June when the first 1,000 is done.

 

[JasonHTX]

Hi guys,
I bought a 21 Tahoe RST back in February. Before that I had an '18 Suburban and before that a '15 Tahoe. My wife likes a new truck every few years and drives primarily in suburbia as a school bus for our kids. Our driving habits have not changed however on this new Tahoe, we have been averaging about 8 mpg. It's advertised as 14 mpg city but were getting barely 1/2 of that. Anyone else experiencing a similar issue? We are at the pump almost weekly. It's a complete disappointment. I've had it in for servicing once under warranty already for an SRS light but they didn't note anything unusual. Any suggestions? Thanks for the help!

Yeah, you should have that looked at. I have a heavy foot and have not averaged below 13.5. That 13.5 was a week span where I was off work and running around inside town a lot.

Normal weeks ... 60% hwy 40% city with some idling mixed in, I get anywhere between 16-18mpg.