Well, I'm back where I started on my OM606

[muleears]

three weeks ago I was attempting to chase away an air leak and replace a faulty SOV. I was doing this because of bad hesitation, poor power and delayed shutdown. Now, after having replaced all the O rings, the K40 relay, all return lines, the SOV and retreiving something I dropped into the valve cover I now have a car that shuts down slowly and still hesitates. The hesitation is much better though. I think it may just be residual air from removing all the fuel lines and injector lines to do the work. But I still have the P0215 code (faulty SOV) and poor shutdown. Now what do I do? This car had the SOV replaced in January after exhibiting the same symptoms. That time it fixed it. Now I have a new SOV and the same old problem. What else could cause the delayed shutdown and throw the code?