Hey all,
Thanks for checking my post here. I'm having an issue with my 2007 X3 3.0si.

A few weeks ago I noticed some hesitation when accelerating while going up the mountain pass. It was very minor at the moment and I figured it was just due to the elevation change. The feeling was absolute loss of power for about a quarter second, about 5 times per minute. This only occurred on the way UP the pass (engine under load).

Same issue didn't happen again the next time I went up the pass nor the time after that.

A few weeks later I went back up, this time it became very obvious something was not right. The hesitation became significant and more harsh. Each cut out would last upwards towards 1 second at a time, and more often around 10 to 12 times per minute. No CEL at the time however. On the way back down the pass and the rest of the ride home everything was perfect and smooth.

Last week as I was merging onto the freeway on an uphill ramp my car lost significant power and struggled with lots of hesitation. CEL finally came on as well. Throughout the rest of my short drive home, the car felt as if it had no power at all. I successfully got it to 60mph to drive slowly in the right lane however at even the slightest incline, the car would begin to slow down and hesitate drastically. When I came to a stop, engine idle dropped as low as 400 rpm and idled very rough. As i pulled into my apartment complex the CEL went away and idle once again seemed normal.

CEL codes as follows:
P1017
P114D
P114B
P0303
P0302
P0300

Recent maintenance to include:
Valve Cover and Gasket about 1500 miles ago
Oil Change about 1000 miles ago (Checked regularly)
Spark Plugs about 5000 miles ago
Air Filter about 10000 miles ago (Cleaned last 1000 miles ago)
MAF about 5000 miles ago