so my passat wagon had new plugs as well as wires replaced approximately 6-7 months ago. as of recently, she started running rough again.... after i start the car and let the idle drop, the car starts to shake/run rough. the check engine light is on and the sensor reading/diagnosis is misfire in the 6th and 3rd. if i let the car continue to run after starting it, it eventually (w/in 2- 3 minutes)stops shaking/running rough. it seems that the car runs fine once it is warmed up. my mechanic does not beleive that it is an air issue and he doesnt believe that it is the ignition coil. but i will add that there is an appearence of oil on the plugs.
misfiring on new spark plugs on 2003 Volkswagen Passat
by ginnydog in Richmond, VA on December 04, 2010
ANSWER by Visitor , June 10, 2011
On my 2004 1.8 Turbo, the OEM plugs would back out. Complained of an oil burning smell and the dealer could not find the problem... Checked the plugs and Replaced with new NGK (OEM spec.) and everything is OK. Plugs were so loose they could have pushed out completely. Your six cylinder may have similar issues if you see black oil fouled threads and blackened downtubes on those cylinders