Misfire E53 2001 X5 3.0i - P0300, P1349, P1347
Hello, I am posting this tread in hope to find resolution for the issue that I have and to help in future, to everyone who might face same problem.
Here are details on what was going on and how I got these codes. I am not sure if this is related but it is better to mention all the details.
First I couldn't get the inspection sticker as two monitors were not getting ready 1. evap 2. secondary air. I was reading thru many posts and I found valuable information on how to check specific part or system functionality. Because BMW dealer told me not to bother with EVAP, (MA allows 1 monitor not to be ready) and that SECONDARY AIR should be fairly easy to fix, I started on checking secondary air for simplest first as that was suggested by many on this site. I found vacuum lines to be brittle because of the age and exposure to temperature change, so I replaced two pieces, one on the SAP (Secondary Air Pump) check valve, and the other on the back of the engine, on the other side of that same plastic pipe. I also replaced check valve, oil separator (PCV valve) with all hoses. At this point car was working fine, I just coudn't get the monitors to set. Then after more reading and checking I found running valve (DISA) to be broken so I replaced that with new one. I found O2 sensor (Bank 2 sensor 1) to be slow and replaced that too. At this point car started misfiring. I rechecked and rechecked and I can't find anything that I did wrong, unless DISA is bad, which is not likely. Because I get random missfire P0300 and specific cylinder P1349 (Cyl 4 misfire with fuel cutoff) and P1347 (Cyl 3 misfire with fuel cutoff) I tried replacing spark plugs 2 times, swapping coils between 3 and 6 and 4 and 2 and nothing would change these codes. Now there is interesting thing, I don't get codes if I disconnect MAF sensor. What does this mean?