Pinging with 87 octane

[JR-SPEED]

It sounds like your truck is running a lean mixture,and thats why you are getting such a good gas milage and the pinging. p.s it is possable for the timing sensors to off a little bit because they are what tells the computer when to fire of the fuel injectors and when to light it up.that why sometimes you get one or two vehicles that are much faster or slower that others that where built on the same assembly line.