have an ex police octavia estate 4x4 6 speed 190000  plus miles, been running well, but recently had a  strange thumping noise from engine, no lights have come on, no loss of power, but when you touch the pipe from front to the EGR, (DRIVERS SIDE) you can feel the throb, and if you remove the rubber hose the throb is loud, is this the EGR valve, which had a good clean about 6 months ago

 

cheers in advance

appears to be comming from the turbo area, loud throbbing  noise, can't find anything leaking or lose, no lack of power, stil accelarates any clues?