wifes car is getting crap gas milage. she has 65k on hers right now. is it time for a spark plug change??? she has an 08 auto. don't know for sure her miles per gallon,but i do know it's bad. any tips to improve gas milage??

 

what was she getting before and what is she getting now? I changed mine (spark plugs) out at 71,000 miles and the stockers were just fine and gapped @ .033
I ended up putting NGK 4306's in there (gapped @ .035) and may have a slight mileage increase, but then my mpg has always been good with my '08
I can get as high as 34.7 mpg to and from work, I usually average 27 to 28 mpg with some local driving included. if I am doing all local driving it will drop to 24 to 25 mpg depending on how I am driving.....

 

Gonna need some more info mightymouse, like what its dropped off to, and what have you tried or not tried yet?

 

Wow I get bad mileage with mine. I am lucky to see around 25mpg, but I do mostly around town and maybe 10 miles on a highway a day. Hard to say, typically I am around 23-24. I have found that if I do any spirited driving, merge quickly, ext once my milage is down to 22-23 it won't come back up quickly.


Also found this old post where people posted what is "normal" for them with there SS's.

https://www.chevyhhr.net/forums/hhr-ss-45/official-gas-mileage-thread-12859/

 

I average 23MPG and i do 90% highway driving but im fine with that. With all the mods im not suprised

 

Found these cars do not like short trips where the eng doesnt get up to temperature.....I see 18-20 cold but 30 -40 warm.....that auto cold circuit and not being in lockup make a difference.

 

My mileage has been incredibly consistent since day 1. Overall average is probably somewhere around 26 MPG. I don't think I've ever had anything lower than 23-24 MPG on a tank, and that is with a lot of local driving.

If I'm doing a lot of highway driving, I can average 28+ MPG, with 30 MPG a few times.

The peak efficency for mileage on the highway is about 65 MPH. Once you get up to 70+ MPH, the MPG drops significantly. It seems the 40-60 MPH is the sweetspot.

Also, using 92-93 octane gains me between 1-2 MPG.

 

gonna have to set it up to see what she is doing. i know she can have a heavy foot at times. her daily commute is 76mi rd trip. at 5 days a week,that's 380 miles. i would say about 7-10 miles of that is city driving. she says she is filling up once week. my ss gets really good gas milage,but i think only because it's a 5 speed.

 

My auto gets 21-24 MPG in town (the higher number is summer] and 31-32 highway under normal driving. I can go as low as 20 MPG if I drive in anger.

The auto's do ok mpg wise.

 

How is 380 miles out of a tank bad?