Anyone help me with this one. How accurate is the fuel mileage indicator on the dash? It's showing around 15.5-15.6 around town (mixed driving), but I haven't filled it to the top to verify if it is even close.
I'm trying to understand why 89 is recommended. If 87 is fine, why don't they just say 87?Your truck doesn't need 89 octane. It will run fine on 87. 89 is recommended but not necessary.
Thanks for the post. Not sure the PCU can tell what octane you have in the tank. However, it may be able to detect ping or knock and adjust accordingly.I remember reading about this somewhere don't quote me on this but...89 is recommended because that's what they designed the hemi to run on.
87 is okay because the PCU will just adjust the timing a bit for whatever fuel you have in the tank.
From what I remember running 87 may mean a slight decrease in hp/tq but I've never noticed any change in MPG.
Like I said I don't quote me here I am just trying to think back to an article I read about this subject...