Purchased a 98 reg st24 in november, 105000 miles on clock. Got full service history with it. Last job done on it was last August when it had an overheating problem, engine was stripped and had valves checked,found to be okay. IT has allways seemed to lack power so i had it put on rolling road to test hp and was found to be 40hp down{mid range crap} initial check looked like cat was nakad so had it replaced+ emmisions check which ruled out oxy sensors. Still no better put it on computer to see if any faults, came back with i.m.r.c. fault was told that the solaniod control might need replaced or flaps could be sticking. Is this the cause of the power problem or could there be other reasons ? ie mass sensor Please HELP !!!