I just got an 05 STS4 V8, 30K miles and I love the car! The one thing I've noticed is that this thing is a bit of a pig when it comes to gas. I had a 400 mile trip home and the best I could do was 19mpg and that was with the cruise set at 75 and no traffic to speak of.

Is this normal? Thanks!

 

Rated: STS-4 .. City 17, hwy 26 (4.6L engine/5-speed auto trans)
at 75mph, its gona be lower, that is a lot of wind to push.

Q: Is the transmission shifting tohigh gear?


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This Christmas holiday I drove to Charleston, SC from Tampa, Fl and back. Roundtrip I avgeraged 22 miles per gallon and I kept my speed around 80 mph. I have an 05 sts4 with the 1SG package.I have never seen better than that rating since I have owned the car.

Jono

 

I think so. It looks like the tach is at or around 2500rpm when the car is between 75-80mph. I thought that seemed kinda high though...

 

I am sure fuel economy was not what you were concerned about when you bought v8 powered 4wd sedan. Driving habits have alot to do with MPG, along with fuel quality and air pressure. Driving 55-65 mph would help economy, but the drive maybe more boring.

 

nope .. 2500 to 3000 rpm is about right for 70 to 80 mph ...

hey, when all those Hydrogen cars arrive, the demand for petro will dive and we will be buying the cheapest petro in history then.

 

It wasn't the #1 item on the list, but most of the other owners I've talked to are at 21-22mpg under the same conditions. I'll try driving at this 55-65mph you speak of and see what that yields.

On a sidenote, my good friend was mocking me because his GMC Sierra Denali is capable of 20mpg on the highway and he doesn't have to keep it at 55mph.

I still love the car!