Still No Power >:/

my stang is always putt- putting up hills , espesially in overdrive , i changed the fuel filter wich was long overdue , changed spark plugs , cleaned out the plenium and upper intake , switched to mobile one synthetic 5w-30 , installed an underdrive pulley kit ,and loaded it down with a whole lot of fuel and oil additives .... but its still slow as hell !!! , i dont know what to do .. i have noticed however it is much worse in overdrive it seems like it needs to rev higher , it usually fluctuates between 1000 rpm and 2200 and never goes any higher , no matter what the load, that may just be normal i dont know , but it seems that when i take it out of overdrive where the revs go to about 3500 it drives up hills alot better and their is no ticking sound coming from the passenger side of the engine , i know what your thinking just drive without the overdrive right , but then ill get even worse gas milage , its not throwing any codes either , the last one it threw was the cam position sensor , but thats done been changed already ... any help?


95 mustang 3.8 - auto