i saw that, too. another thing to confuse my search! i had a Cadillac in high school; they also recommended using premium on that, but i didn't notice anything by running ethanol. but surely something to think about.

i wish i had time to go pi$$ around test-driving vehicles, but i have a job!! hopefully saturday! i also plan on looking at an '07 impala.

 

You don't need premium. It says you don't, but recommends it. My mom's G6 has that same engine and it doesn't require premium.

 

very true. it does not "require" premium. I have been using regular in mine since I got it and have not heard 1 knock.

The only hhr that requires it (although can run on regular if needed) is the SS. If you flip open the gas cap it even has it written in there, premium... None of the others have that.

 

I haven't run premium since gas hit $2.75 a gallon for regular. Never had an knocking or economy issues and minimal performance issues.

 

I got the 2.2 since the 2.4 requires premium fuel. Actually, it says premium is recommended, but not required.....which means the engine will run on regular but won't have the zip of premium....meaning you're back to 2.2 performance.

 

You're all going to think I'm crazy, but since gas is somewhat cheaper now, I think I will just try premium in it when I fill up just to see what it does...

I know you really can't do much in just one tank, but who cares. Give it a little treat since it's probably never had it before. I gave it a dose of fuel cleaner to help it too. I know you guys all probably think I'm wasting my money, and sure, I guess I am.

I'm also the same person that was running premium in my Lumina when gas hit $4, because I truly did get better mileage, and I calculated it out and it was worth the extra cost of the gas for the increase in mileage!

(I'm such a dork)

 

I burn mid grade in my 2.4 most of the time.There's a definite difference in power and mileage between that and regular, but I didn't notice any when using premium instead of mid grade.

 

i've read articles where it has absolutely no effect on vehicles that do not require them (i.e. your 2.2L hhr, lumina, and my grand prix). i didn't get one bit better with premium because GM did not require/recommend it. it's also not even a treat as those vehicles don't need it. ! but, opinions vary.

 

there are a lot of posts on here where people have done testing of the different fuels. Some people got better mileage and said their power was increased, others said it didn't do jack.

For me personally, I won't be putting prem in mine in less i see hard numbers and a distinct cost to benefit ratio

 

i tested premium for a week , thats over 1650 miles for me , 275+ miles a day 6 days a week. i didn't do any actual performance tests , but i felt no difference. i may have got 1/2 mile per gal , if that. i check on paper as well as the dic dash thingy. most was on the hwy. i tryed it going different speeds on different days. if you can drive below 60mph you may see slight difference. but this is also true for me on regular. some may get different results. but i doubt it. i posted the results on here in anouther post/thread.