Vehicle is a 2012 Jetta GLi - 2 liter turbo
I'm getting a P0301 code - misfire on cylinder 1
Only I never noticed it while driving. Just now however, after getting the code read and doing an oil change, sure enough it started idling rough.
Add some throttle, or get it under load and voila! Nice and smooth again.
This doesn't sound like coilpack or a plug issue to me, as generally don't those issues get worse under load?
Clogged injector maybe?
I'm thinking about swapping the coilpack from cyl 1 to a different cylinder to see if the problem moves with the pack.
Other thoughts?
Scott,
Loosen the oil filler cap when the car is idling and see how easy it is to lift up off the valve cover. If it takes a lot of effort, then it's likely that the crankcase vent valve has a punctured diaphragm. This will cause a lean running condition, especially at idle, as the car is getting "unmetered air" from the crankcase. if you do find this to be the case, get it fixed pronto. The rear main seals on these engines are "bonded" to a metal carrier plate, and excess crankcase vacuum will suck that seal right off the plate. That's when it starts to get expensive.
