no power when accelerating
 

whenever i leave from a stop it drives fine if im going slow but when i try to get on it or go up a hill it seems like theres no power, it just recently started i know i need a tune up (havent had one in awhile). its a 98 d16a vtec motor pretty much stock with a lightweight flywheel and stage 2 clutch, even when i rev it up when stopped it goes up slower than usual. thanks in advance