2005 X type diesel 2.0. I have recently started to hear a hissing/air rush sound when accelerating beyond slowly. As speed picks up the sound goes away. There does not seem to be any effect on power but i think economy has dipped by approx 3mpg. Any ideas??

Sounds like clutch is slipping. If you accelerate and it does not respond I would say clutch assembly is bad.

this could be a bad wheel bearing.

do you hear a loud hissing sound when you take off?
Could be the cat converter.

if not that, I've seen CV axles that caused poor take off and vibration.

let me know what you find.

would be worth having the cat converter check for blocking the exhaust system

Great to hear. Good Job!

Sounds like under a load. Could be transmission torque converter.

well, you don't really hear air when you press the brake pedal. You might hear hydraulic fluid going through the valves in the master cylinder, that sounds like air flowing through a vent. But, I assure you, it is not air.

One can press and pump on the pedal when the car is off and hear the 'rush' of fluid which sounds kind of like air rushing out of an inner tube.

It's a common mistake to believe a rush of air is being heard when pushing on the brake pedal.

replace air filter.and fuel filter.

had the same issue, had someone look and it seems the noise was caused by heat shield being loose covering exhaust system. Have that checked out.

can anyone tell me where the intercooler is on a 05 plate jaguar x type 2.0 diesel thanks