Purchased my SRT at 30k for the next 30k it ran like a dream, i could unleash it whenever i pleased. Now at 65k it does.not have the same performance, at highway speeds or even at dead stops it lacks significant acceleration and sometimes it feels like.im driving a nkssan sentra instead of an SRT.vehicle. the problem is intermitent, what could it be? Ive replaced the throttle body, SC pulley, air pump, SC clutch, crank.sensor and plugs and still no fix... please help.

Thank you