My 2002 Ba xr6t I bout a year and a half ago with 155 thousand on it and about 20,000 ks after that pretty much as soon as the dealership warranty ran out my car started doin the brrrr under boost and got worse.Took it to ford and they did a diagnostic and said it was coils,changed them and sparkies and electronic boost controller,all good.10,000 ks later its back again and ford wanted another $120 for another diagnostic,yeah bullsh*t so ive delt with it for the last 20,000 ks,frustrating but ive cleaned the boost solenoid numerous times and throttle body and have new ngk sparkies and since hitting the 200,km point my car is now getting the rough idle.started off worse as the car got warmer but now itl do it all the time,on cold start shel misfire for about 2mins till it warms up cos ul here the exhaust caughing if u stand at the back.and if u give it a lil rev to 2000 rpm and take your foot off itl drop to 1500 and sit there for 5 seconds then drop to a 1000 and then slowly down to 700 so its missing hardcore and I dont know wat else to look for.