just wondering why my truck gets 17-20 miles to the gallon and runs so smooth with shell rotella 15w-40. i've owned this truck all it life used only 15w-40 in it and every one tells me it going to kill my miles per gallon and make the 4.6l triton brake. will i have 166,500 mile and never had any problems. i have a friend how own the same year and idenical truck and he gets 15 to 17 miles to the gallon and he runs 5w-30 shell oil. wonder if any one knows why my f-150 has more power and gets better and runs smoother than his f-150

just leave me a message telling me what you think.

 

I think everyones foot is different. You probably get better economy because you drive your truck more rationally than the next guy. The fact that you have 150k plus mileage on your vehicle probably is a good reason for you to b getting better mileage. Shell 15-40 oil is very good oil, you probably have maintained a smoother cylinder wall and do not have the loss of compression that your buddies truck probably does. Why don't you run an independent cylinder pressure test and see which one of your trucks is carrying the best compression. Be careful not to pull the spark plug threads though. lol

 

thank you. i'm going to try that next time it warms up.