I removed the EGR valve on my 2005 TD5 Defender last night using a kit from a supplier I have used before on my older 110 TD5. When I started the car up all was fine but when I revved the engine up the EGR solenoids started to buzz and vibrate. They do sometimes stop buzzing if the car is left to idle for a while. The proper pipes have been removed from the solenoid and the ends sealed off. I'm at a loss as to what may be causing it. Anybody got any suggestions?