[halik008]

So all the sudden today on my way to work and back from work my N54 E90 started experiencing these power jolts/surge spikes.

At first I though it's a misfire, but its actually random power surge. It's only happening while cruising in vaccum just maintaining speed. My boost gauge actually registers quick spike in boost and my timing shoot up into advancing more.

But it's only a random spike/jolt and happens maybe 2-4 times in 12 miles covered. No issues performance issues otherwise in WOT.

No engine codes other that the usual no kitties and two shadown codes from running inline Walbro.

Any ideas what it might be?

07 335i M/T
JB4 G5 ISO
no kitties
Rennart CBE
ARM Motorsports Stepped FMIC
AL charge pipe
Tial Q BOV
NGK 5992 Plugs @ 0.022
CTS DCI
Fuel it STG1 inline Walbro
Running E57

[Paanzerfaust]

Valve cover or Vcg most likely. Same exact symptoms I had at first before it got worse and I wasted time fixing other things lol. If you take your cowl and engine cover off and see oil anywhere then it's a guarantee.

My cars also an 07 and my gasket just went bad this past year too, same thing where I only had issues while under vacuum and everything. While you're in there light as well spend the extra $100 for new PCV parts or if you were considering an external pcv system you could do the whole thing right now.

[halik008]

Originally Posted by Paanzerfaust

Valve cover or Vcg most likely. Same exact symptoms I had at first before it got worse and I wasted time fixing other things lol. If you take your cowl and engine cover off and see oil anywhere then it's a guarantee.

My cars also an 07 and my gasket just went bad this past year too, same thing where I only had issues while under vacuum and everything. While you're in there light as well spend the extra $100 for new PCV parts or if you were considering an external pcv system you could do the whole thing right now.

valve cover has been redone ~4k ago so it should be that. High side PCV has been update already. Low side I'm waiting for AD engineering to take my damn fitting order!

[Paanzerfaust]

Originally Posted by halik008

valve cover has been redone ~4k ago so it should be that. High side PCV has been update already. Low side I'm waiting for AD engineering to take my damn fitting order!

Hmm, because of the symptoms I'm still thinking it has to be PCV or vacuum related but I guess it could potentially be your injectors leaking if your logs show any symptoms. Depending on how long ADE is gonna take you might want to just spend the $30-40 for a pic valve