[blackwind1]

Hello Folks,

I recently have some rough idle on my car after sitting for 4 days without running.
so, I figured it is spark plugs and coil issue and changed it.
While changing this, I saw oils on my coils in most of the cylinders and found valve cover is cracked.
So, replaced with new valve cover with new gasket. also plugs and coil.
I still get the rough idle in the morning starting up. but ok after driving for awhile.

What could be the issue?
Injector? or intake valve carbon build?

I sometimes get vacuum leak code when I WOT on 3rd gear.

Only mode is JB4 and DCI. but JB4 is off now.

Please input some solutions. I just did paid alot for those job and want to go better solution.

Thanks in advance.

[Wolf 335]

Your injector is leaking overnight.

Once the excess fuel burns out, misfire stabilizes and you're back to normal operation.

As for the vacuum leak, inspect all vacuum line connection points and make sure one didn't slip off. You may also want to replace all vacuum hoses in case there is a hairline crack somewhere.

[ak22]

I was having the same misfire issue on my E92 335i.
If the engine is shaking/misfiring only on cold start up (i.e. after the car has been off 5+ hours) it's more than likely that your fuel injectors are leaking.
I replaced all 6 fuel injectors and the shaking/misfiring has been resolved.

[MrAC]

Originally Posted by ak22

I was having the same misfire issue on my E92 335i.
If the engine is shaking/misfiring only on cold start up (i.e. after the car has been off 5+ hours) it's more than likely that your fuel injectors are leaking.
I replaced all 6 fuel injectors and the shaking/misfiring has been resolved.

Sorry to thread jack. But did you ever have misfires after starting your car up let's say about 5 mins after you've been driving around? Reason is, during cold start, I don't really notice a misfire but I think it is there, but let's say I get the car to 120C, turn it off to grab something quick from the store and start it up, it'll misfire and sounds ugly for like 20 seconds but then calms down after that.

Changed my sparks and plugs..is it time for injectors?

Thanks

[ak22]

Originally Posted by MrAC

Sorry to thread jack. But did you ever have misfires after starting your car up let's say about 5 mins after you've been driving around? Reason is, during cold start, I don't really notice a misfire but I think it is there, but let's say I get the car to 120C, turn it off to grab something quick from the store and start it up, it'll misfire and sounds ugly for like 20 seconds but then calms down after that.

Changed my sparks and plugs..is it time for injectors?

Thanks

No, it would only misfire after it's been off for hours (at least a couple of hours)
If I drove it around, then shut it off for a short while, even like an hour, it would start up fine without misfiring or anything.
I'm sorry I don't have any idea what could be causing your issue.