2000 X5 idle missfire

I have an intermittent idle missfire problem. I originally had this problem & codes p1158 & p1160, as well as p0171 & p0174. I checked fuel pressure (good) & smoke tested it and found no air leaks, installed new Iridium plugs. and installed a MAF I got off the internet and the X5 even ran worse. I then purchaesd a Bosch MAF and it ran great for a couple of days but then started to miss again at idle. I no longer have any codes, but after you set for a few minuets in drive it will get a real slight shudder/stutter/miss that the longer you set there the worse it will get. The fuel trim numbers are good now too. I would appreciate any suggestions you may have. Thx Racecar80

Check your ignition coils.

I visually checked em when I changed the plugs & they look good, plus there's no miss at all under a load.

Originally Posted by Racecar80

I visually checked em when I changed the plugs & they look good, plus there's no miss at all under a load.

I had an engine misfire with my 2001 4.4i. The problem ended up being mushy oil separator hoses. They're located near the back of the engine underneath the "BMW" cover on top of the engine. Might be an easy (and inexpensive) fix if these are the problem. How many miles are on your X5?

It's got about 80k. I checked those, we're good there. I smoke tested the engine and didn't find any air/vacuume leaks.