hi guys, i just have a oil sludge repair done on my a4 1.8t. after that my car was not up to normal specs. i went back to the dealer and they say nothing was wrong with the car. few months later, had to change spark plugs, ingnition coils, and gascaks. fuel filter and fuel pump. wtf! can someone tell is the dealer ripping me off? btw 91000 km 2003 a4 cvt.