Hi there, I have had a problem with oil leaks with several valve cover gasket replacements, replaced my entire pcv system 2 months ago and just 3 days ago my dad brought over my uncle who's an independent mechanic. Well I was at work and I really did not want him to work on my car since he's never worked on german cars. Anywho, the day after I went to turn on the car and it began to shake a little as if misfiring. I turned off the car, popped the hood and made sure he had plugged them all in correctly and that no oil fell inside. Everything was okay, then i checked all my pcv hoses and all were plugged in right and not damaged. Turned on the car and still rough idling, so I cleaned my throttle body, maf(even unplugged during run also to make sure it was working and that it roughed idled even worse to know it wasn't maf). Checked my intake for loose boots or clogged filter. Still all the same. So checked all my vacuum hoses today and the one from the secondary pump(blue thing under wiper fluid) that ran to the top of the plastic housing that I had replaced a while back, so I went ahead and decided to replace all. I ran out of silicone vacuum hose so I only replaced the ones on the top of the throttle body and not the one that runs to a "Y" and runs along the the back maybe near the purge valve and the other obviously in front of the intake manifold under the coil pack. Still same rough idle. The rough idle stops at 1200rpms+ and the throttle body can be heard opening and closing as if it does not know of what to do unless i press gas. I'm pretty sure there is a vacuum leak somewhere and also a note, my father said that my uncle had dropped a socked behind the engine/right side and was poking around his rod magnet to pick it up. I unplugged the long vacuum hose that goes from the secondary pump to the first zinc plated block on top of the housing sitting on the throttle body, got suction going towards the left and no air blowing from the other end if it is supposed to? This is where have left off, there is a hissing sound behind the engine around where the throttle body is, what could it be? I'm getting bank 1 and 2 fault codes saying it's running too lean along with multiple misfire codes and maf and purge valve fault codes, also says a "leak". What could it be? maybe the combi valve??? any help please, tried driving but it runs really rough and I hear the heater core gushing coolant crazy and a deep pop sound around the throttle body area.