[thenxtjrdn]

I've been a keen observer of this forum and have learned a lot from the discussions. However, this is my first post as I'm completely stumped and need your help.

I drive a 328xi SULEV (N51) with 120k miles, but I reside in a non-SULEV state, so the dealer does not recognize the warranty. Recently, I had a Valve Cover gasket leak that emitted a burning smell. I decided to tackle it myself, using the DIY guide on this forum. Based on the recommendations, I replaced the Valve Cover, Valve Cover Gasket, Spark Plugs, and Eccentric sensor in the same job. I got all parts from FCP-Euro. The job was lengthy, but I managed to finish it without major issues. I did a visual inspection and did not notice any leaks or pinched vacuum lines.

However, after completing the job, I noticed that the idle was bad, but the car drove fine. A few minutes later, the SES light turned on, indicating misfires that were not there before. I checked the codes on my Foxwell NT510, which showed misfires in Cylinder 2 and 5 (29CE and 29D1) and a code for the Air Mass System (2D06). I went back in and checked the wells, but they seemed fine. I also moved the ignition coils from Cylinder 1 to 2 and Cylinder 6 to 5 but the rough idle persisted. A few minutes later, I got codes for misfires in Cylinder 4 and 5.

Following another forum member's advice, I decided to clean the VANOS sensors. I cleared the codes and restarted the car, and it ran fine. I drove for 20 minutes with no codes or issues at idle when at red lights. But when I turned off the car and turned it back on, the rough idle returned, this time with Mixture Control codes for running lean (29E0 and 29E1).

I'm at my wit's end and completely stumped. I would greatly appreciate any help or support you can offer. Thank you.