This has been bothering me for a while i am only getting 22mpg. I do go to a lot of stops, but a lot of times im also going a constant speed of 60. and i try to hyperdrive as well.
I have 20 inch rims on but dont think it should effect it that much
My air filter has already been replaced.
I only have ~40k miles

I know the impala is rated a lot higher or are those just fake ratings, anyone else have some real life ratings they can provide or anything i should look to get checked out first.
Especially guidelines so i dont take it to a repair place and they end up changing everything, to charge me a lot.

even when i reset odomoter and drive in highway it ends up going down to around that much. The only time i got a good mpg was when i first drove it off lot, after i filled it up with gas it just started staying low.
is there a trick to calculating mpg with odomoter better for certain trips without having to reset it everytime since it just keeps averaging everything out

I have been getting around 22-24 MPG in the city and i just got 32 MPG on my vacation last week. I went 426 miles on 3/4 tank of gas. I have 81,000 miles on my 3.4 liter.

By the way welcome to the forum!

Those 20's will cost you mileage, Have you had your car re-tuned for the 20's so that your speedo is correct?

I cant get 27-29 what a joke but 26 on regular