Having only driven a 2.2, that"s all I know. But from talking to other drivers with a 2.4, their economy is better. My little engine that could serves me well, so overall I can't complain. But struggling to maintain 24-26 mpg is a challenge. I'm saving up for that 3.0 ecotech! Yea, man!

 

I have the 2006 2.4 VVT and I average around 26.8 MPG with a HEAVY Foot. Now that I am driving calmer I am sure it will climb up again. At one point I had an AVERAGE of 30 MPG! Now one difference I can say is power and sound.... the 2.4 does sound much deeper and nicer IMO. Those that run their 2.4 on the recommended octane of 91+ know that this little wagon really can move its own weight around pretty well. I have been more than impressed with my HHR so far and love the powertrain. If they still offered the 2.4 in the newer models of the same class I would go for it but I believe its only available in the Malibu now. At any rate; a 2.4 run on proper 91 or above octane far outshines the 2.2 I believe. Just some biased info coming from a 2.4 owner

 

After car shopping and trying to get something with all the options mine has, I'm actually thinking of putting an engine and tran in my car . Found them with only 35,000 miles. Then I will have everything I want.

 

That's my plan , fresh engine and transmission, when this one let's go! 205,000 miles and still good compression, drives well and no rust!

 

Mine has almost 250,000 miles I rely on my car for my business. After looking all week at HHRs that didn't compare to mine with options that I want and honestly mine is nicer than the 2010 and 2011 I looked at. I have decided to replace my engine and tran with a low mileage one and get many more years out of the car I love ! And no car payments.

 

That's the spirit!! Just a suggestion, before you install the replacement, change the timing chain and gears and guides! Maybe the water pump and thermostat, I'm sure you know what a pain it is to change those with the engine in the HHR!