[blau iii]

So this past weekend I did my VCG using a new VC. I also replaced my PCV with the RB one and did blow by vent hose as well. I also replaced the vacuum lines to the canisters as well as the two that go over the top of the engine. I didn't have enough time to do the rest of the hoses.

I noticed that when I start the car up in the morning, the engine chugs a bit for about 15 seconds, almost like a misfire but not as violent.

I'm not seeing any codes. Could this just be that the engine can breath easier? Anything else I should check? Once I start driving the car is in tip-top shape.

[NoQuarter]

Missing a vacuum line connection maybe.

[blau iii]

Originally Posted by NoQuarter

Missing a vacuum line connection maybe.

I thought that too but the ones I replaced are still good and tight on the nipples.

[vickers]

I just recently had a similar experience. It started out as a cold start shuttering like you described, and grew into an all the time rough idle.

Changing the valve cover on the n54 requires you to touch a lot of parts that can cause rough idle symptoms. The simplest (and cheapest) solution is to go back over your work. Make sure your coils are seated fully, all electrical connections are secure, and fuel lines are tight. Also, check you didn’t pinch any wires. I know I got pretty rough with the wiring harness trying to wrestle my valve cover off.

If everything checks out there, try flashing back to stock and doing a throttle reset. (Assuming your tuned)

I ended up replacing my plugs and coils to smooth out my idle. It seems my 10yr old coils didn’t like being removed. Haha

[dsjr2006]

The vacuum lines become brittle over time. It's possible that one cracked when you changed the valve cover. Might be a good idea to recheck your work and just replace the lines with silicone lines while you're in there.

There are a bunch of threads about the vacuum hoses and what to order for replacement/upgrade.

[blau iii]

Originally Posted by vickers

I just recently had a similar experience. It started out as a cold start shuttering like you described, and grew into an all the time rough idle.

Changing the valve cover on the n54 requires you to touch a lot of parts that can cause rough idle symptoms. The simplest (and cheapest) solution is to go back over your work. Make sure your coils are seated fully, all electrical connections are secure, and fuel lines are tight. Also, check you didn’t pinch any wires. I know I got pretty rough with the wiring harness trying to wrestle my valve cover off.

If everything checks out there, try flashing back to stock and doing a throttle reset. (Assuming your tuned)

I ended up replacing my plugs and coils to smooth out my idle. It seems my 10yr old coils didn’t like being removed. Haha

My plugs/coils are less than a year old. I did go back over everything I touched and it was all buttoned up tight. I'm on JB4 only right now (planning on MHD BEF in a few weeks) I didn't know I could do a throttle reset with that, any idea how?

Originally Posted by dsjr2006

The vacuum lines become brittle over time. It's possible that one cracked when you changed the valve cover. Might be a good idea to recheck your work and just replace the lines with silicone lines while you're in there.

There are a bunch of threads about the vacuum hoses and what to order for replacement/upgrade.

I did all the lines to the canisters and the ones that go over the engine. I ran out of time to do the mess that goes along the turbos. I'm going to tackle that this weekend and hope that fixes this.