Pulled Codes After X5 Started Misfiring - Confusion Ensues...

[Bayerische E53]

Hi All,

My X5 started misfiring BADLY a few weeks ago. I used a friend's GT1 to pull the codes and the only thing we found was that Cylinders 1 and 5 were misfiring. We thought it might be the spark plugs so we changed them. This only helped the issue but did not completely remedy it. The car kept misfiring slightly. About a week and a half ago, the misfiring came back pretty badly. So, by power of deduction, I figured bad ignition coils were causing the problem. I bought 6 used coils from a friend who had a set sitting around that he pulled off his racecar. I figured I'd replace the coils in Cylinders 1 and 5 and keep the other 4 as spares. After all, I've got 3 M54 cars. Fair enough; so I thought.

Here's where the problem begins. I decided I'd wait to change the coils until I got a Peake Tool to make certain of the codes. The Peake Tool just came in. I pulled the codes and I'm stumped.

The Peake Tool did not report any codes showing that the coils were bad. According to the Peake Tool, not a single coil is bad. Huh? Further, the Peake Tool says that, among other woes, 5 of my cylinders are misfiring now as opposed to only 2 just a few weeks ago. Huuuhhhh???

Maybe someone can help me interpret the codes the Peak returned. Those codes are:

CA: 02 Sensor Control Limit, Cyl. #1-3
CB: 02 Sensor Control Limit, Cyl, #4-6
CC: Idle Control System, Idle Speed Not Plausible
E3: 02 Sensor Adaptation Limit, Cyl. #1-3
E4: 02 Sensor Adaptation Limit, Cyl. #4-6
EE: Misfire, Cyl. #1
EF: Misfire, Cyl. #2
F0: Misfire, Cyl, #3
F1: Misfire, Cyl, #4
F2: Misfire, Cyl, #5

Apparently, Cylinder 6 isn't misfiring. How is this possible when the other 5 are? How could the GT1 not have picked this stuff up? Two preliminary questions: 1) Did I not use the GT1 properly or 2) Is my Peake Tool wrong?

Well, I guess I should ask one more question: Am I doing something incredibly stupid (i.e. Am I an imbecile?)?

I could have sworn that it was bad coils causing the misfiring. If my Peake Tool is correct, what does all this mean - bad 02 Sensors? Boy, that would be a bear.

And what about the idle speed not being plausible? The Peake Tool did not report an ICV/DISA code so I imagine those aren't causing the idle speed code. I would imagine that the misfiring, which caused a low, rough idle, has triggered this code - but, because I have apparently been wrong about everything else, I'm cautious about jumping to such a simple conclusion...

I appreciate any help.

Thanks, guys and gals.