Man, last week was reading somewhere that the 05 up 4.6 was actually factory tuned for premium, but the knock sensors are so effective, its not required...just for the heck of it, filled with premium...didnt feel any different(but wasnt going to the dragstrip either, just driving to work...). Weird thing was, yesterday when I went to fill up, had over 270 miles on the trip clock showing- normally always 230-something...the car has averaged 17-18 mpg like a clock on non-highway mileage forever, one tank of premium and it goes over 20 for the first time...hmm, tell ya what- premium next trip to the track
if its pulling enough advance to pick up the mpg about 10%, it ought to be getting a bit more hp at full throttle I would hope.
last highway trip was 24.5 mpg @ 70 mph, will see what premium on the highway gives next time...27 possible?
That would be not bad for a high 13 second bone stocker...I was happy with 24
