91 Octane wont hurt anything though if your running a 91 tune through superchips. I have been running either 91 or 93 octane in my 4.7 XK for over 3 years now with now problems. Well beside the hole it makes in my wallet.
Printable View
91 Octane wont hurt anything though if your running a 91 tune through superchips. I have been running either 91 or 93 octane in my 4.7 XK for over 3 years now with now problems. Well beside the hole it makes in my wallet.
the HEMIs have to be careful tho with the higher octanes, Im wondering tho if Im losing performance and mpg due to pre-ignition???? Seems to be an issue after researching this is a common topic. I didnt buy my XK for fuel economy but the sudden drop was concerning, Im going to start with 91 and see how it runs... This is going to be an expensive guess and check game
I use Shell and Sonoco 89 by me.
If you've been switching between 87 and 89, try sticking with 89 for a few tanks so the computer isn't constantly trying to adjust between tanks.
Ok Ill do 89 then for a few and see what happens. Still doesnt explain the sudden drop but oh well. No codes, no lights no problem.. I hope!
My memory is escaping me.... how many miles are on it and do you know when the plugs were last change? I noticed a stark decrease in mpg as I approached 30k on my plugs.
Maybe disconnected the battery for the hell of it too.
Ive got 79k and only 2500 miles on the plugs, just did complete 60k service-all fluids plugs front diff bushings belts- when I purchased. I will disconnect the battery to see how that helps...
I disconnected the battery for a min to reset the computer, I will update to see if that does anything...
I hit 17-18 MPG coming this last weekend 6 people plus luggage and both front and rear AC on I did however have my basket and cross bars off. Running no tune just corrected for tire size and on 87 octane.
Literally a minute? Needs like 10-15 for memory to reset (I turn the key on for good measure too)