little problems

hi all how you doing , my little fun needs some help ,, in an old thread i was told my throttle body was the problem . i took it all apart give it a clean up and it seemed ok running and tick over and its still doing ok really , well its not cutting out any more and theres only a slight bounce in the revs now and then . if im driving along a dual craridge way say doing 40 plus im getting this sudden less of power but if i put my foot down it will pick back up no problem ! or if i let off on the gas it will pick back up! i dont think the problem is getting worse some days i dont have a problem at all . is this down to the trottle body ? which iv not replaced have you seen the price of them !! my truck is burning oil and there is a bit of gunk on the filler cap / waters clean , and the temp is ok , sat in traffic it gose to half way and the fan kicks in and its fine . can anyone help me out here ?

cheers ric