Hi I have a 1996 Jaguar XJ6 3.2L LWB auto, the problem I have is that the heater only gets a little warm on full tilt, do you think I have a matrix problem if so how would I clean it out to get it working properly again also the tick over rev's are supposed to be between 750-850 but sometimes they go as high as 1200 what do you think is wrong and lastly when I hit 50mph the car feels like it is struggling until I put my foot down a bit more it stops at 70 mph, I am about to get new tyres fitted next Monday and the tracking sorted do you think that will stop the juddering. Please help. Thanks