i have a question which could be caused by a faulty something or another in the fuel/air monitoring system. my truck, usually when maintaining a speed between 43 and 53 mph, not at any certain rpm, will kinda rev up and down, up and down, up and down... etc, almost like its about to down shift but it doesnt, it just keeps pulsing like that until i mash the gas a little more, and it normally only happens when i am going up a slight-moderate incline. do any of you think it could be due to a faulty O2 sensor, or maybe dirty injectors? or if it is another problem, i will post it in its proper place, but if it is related to a bad sensor then whatever. i also noticed it this weekend when returning from tenn, it did it but not as bad, at around 85 or so