I have a Leon 1.8 20v, have only got it a few weeks. The turbo has started to go into limp mode, it boosts and i'am getting 15 psi boost then driving along and get it some again and it only boosts to just under 5 psi and the turbo isnt kicking in. But I turn the engine off and back on and the turbo starts boosting again. I have went to seat and was told it is carbon build up on the turbo and the guy told me to use a bottle of oxicat but it is still going the same.