I dont own a hemi but does the ownser manual say to run 87 or what?? if it says mid grade or prem then run that and see what u get from there. Plus if u get the gas from a mom and pop place they tend to have water in the taks more then a station that moves some gas.

 

The mfg recommendation for 300Cs in 89 octane. I use that exclusively in our Heritage Edition. If I fill at a station (Sam's Club) that doesn't have 89, then I mix half and half 87 and their 91/92 octane.

Why chince on gas with a $35k+ vehicle? Additionally I add ACES IV fuel catalyst from BND Automotive, which creates a synthetic lubricant for the upper cylinder upon combustion to improve ring sealing and lubrication. Oil analysis from my last change (7300 miles) indicates less fuel content via ring by-pass than normal on a 3k mile change.

For the same reason I run only premium 91/92 octane in my MSRT8 and also add ACES IV. During a recent vacation, highway economy was 22 mpg (vs. EPA rating of 21 mpg) with 4 adults and a baby (and all that baby paraphenalia in the back). That was a fun trip!

 

I was just reading about the rought idling that you guys were talking about.I have a 05c and i get the same thing happening. It doesent do it all the time so i dont no if it is a big deal or not but i dont want it to get more rought.