I am going to be replacing my plugs soon and would like to know if there is any preference on brands for the HHR, mine being an LT with the 2.4L engine. I have seen some posts about using Autolites and also using OEM AC Delco also. Also, I plan to replace the plugs around every 60,000 miles, could I go down to platinum plugs instead of iridium and save a bunch of money without losing performance? Thanks for any input.

 

Personally, I'd stick with AC Delco Iridums.

And unless you are experiencing a problem, replace at 100k. IMO it's a waste to replace what is not broken.

 

At 32,000 I changed to the E3 plugs big mistake had so many missfires bought Ac delco Ird. glad I did now have 50,0024 miles no problems.