I've tested it on 87 octane regular and 91 octane premium with no difference in the results. always at "name brand" places.

 

OP......you have a 2LT which has 17 inch tires as stock. Do you keep them inflated to 35 PSI COLD?

 

Yes I check my tires weekly and keep them at 35 psi COLD! (and, yes they are the 17" tires)

 

Obama says you can save $100's on gas with your air gauge and keep your health care insurance. Oops that's political, never mind.

The most I have ever noticed from tires is nothing. I had a car that always seemed to have low pressure in all the tires, got statistically the same MPG when correct V. low. That was a long time ago, 1967 Dodge Dart.

 

have seen and absolute increase in hwy mpg since cleaning the MAF sensor on my 2006 LT.... have bout 65k on it. was getting, at 65 mph, bout 30-32 mpg...now, on the same hwy route, same weather conditions, getting 33-35 mpg consistently...............so, make sure your MAF sensor is clean........can get the spray(made by CRC) at most any auto parts place...

 

I think the gas companys have started giving us the winter blend gas that gets you 2/3 less mpg too

 

Hmmmmm. .......using the winter blend gets 2/3 less mpg??? So, if you were getting 20 mpg before the winter blend, you are now getting approx. 7 mpg with it??? Don't think that is correct.

 

biggest problem with discussing is the human factor. we ARE different. we drive on different roads and with different habits. some on flat terrain, some hilly and some use cruise, others just can drive more economically.

i have noticed our 2.4aut (40k miles) does average between fillups 22MPG or so thanks to 50/50 city -highway, but on normal road driving appr. 60mph on over 60miles long trips we get between 30- 34MPG. i think its ok result and best HHR can do with normal traffic and normal driving skills.

NOTE: (edit) according to fueleconomy.gov our (2.4aut)hhr should go between 22-28MPG. so when we get better than that, its a win!
Note2: latest calculations on sort of premium gas(euro), at moderate 30F-40F and 16" traction tires
note3: its not the winter blend, its the winter temps!

 

if I was getting 20 mpg before the winter blend and get 2 or 3 less mpg that would be 17 18 mpg

I get 30/31 mpg on the highway and latley I am only getting 28/29 mpg

 

Oh that explains it then. You just used an incorrect "abbreviation" for what you meant...........2/3 (two thirds) instead of 2-3 (or 2 to 3). In any event, that what I recognized it as.