hello i was woundering if anyone could assist me on this problem i have a 02 2.3 ranger and in 5th grear i can hold 70mph. now sometimes this truck runs great and will run 70 in 5th some times it wont it has its moments but it seem to also happen in other gears as well ive spoke to my mechanic and hes done a complete over haul and it hasent really changed wwhat would be my next step to add power gears or chip thanxs for youre help i have 120000 miles on her