Confirm that the O2 code is 2C78?
You aren't running any performance tunes?
Catalysts installed?
Have you disconnected the O2 sensors recently?
Confirm the last time you cleared any DTCs.
What work/tinkering/inspection has been done under the vehicle recently?

So no tunes or tweaks or mods are done. It’s bone stock. I love this car and don’t want or need to mess with it. I have not disconnected the O2 sensors and the cats are installed. The codes were just cleared yesterday when I replaced the battery I also went into that ECU directly and cleared them out. After yesterday’s drive that 2C78 Lamba Probe behind catalytic converters 2 signal code showed up as pending. The CEL is still not on however but the code is stored in the DME.

I replace the Vanos valves with brand new OEM valves I also replace the Vanos check valves with OEM ones as well. As mentioned I replaced the battery yesterday. A few weeks back I replaced the upper strut mount bushings.

About 7 months ago I replaced all of the coils and plugs with NGK plugs prevailed and checked for correct tolerance. I’ve been swapping coils out to see if that helps but there is no improvements there.

I’ve cleared transmission and engine adaptations in hopes this would help but it doesn’t seem to.

I will say that the valvetronic motor gets very hot at running temp. Maybe that’s normal.

This issue is directly related to temperature as well since when I start cold and drive for 15-20 minutes it’s perfection. But then it starts degrading to the point where sometimes the throttle doesn’t respond without me mashing the gas under load. I press more and more and it simply doesn’t do anything until I really get on it. Also it seems perfect at highway speeds and when I really press the gas to go there is no problem with immediate and smooth power delivery from what I can tell.

This issue is a troubleshooting nightmare lol

Thank you for the help!

I have no idea what it means, but that -2.2x% multiplicative value would drive me crazy till I found the source of it. May be totally unrelated though.

I could be wrong but I believe even though it's probably well with-in 'specs', should ideally be 0%. The fact that it's (in my mind) significantly different than the other bank makes me wonder if you have any air/oil leaks on that side.

2% +/- is not crazy for LT and ST fuel trims. When you get over 5% and 10% you have an issue. I believe codes trigger on BMWs at 10% +/- LTFT. At least that's how it was on the M54.

Must admit I've never really worried about fuel trims. If a code popped for one it was usually a vacuum leak. O2 sensor codes were usually heater circuit errors.

So at this point, do you guys think the O2 sensor code is a false positive? I'll inspect the wires tomorrow. I can just replace it if you feel I should.

Also, looking at the data I posted, it seems that there's nothing that really stands out as an issue. Even the smooth running data is all very close in the dead center of the spec.

My drive home today was the same. Beautiful highway driving, but jerky on normal roads. Typically the shudder / jerkiness occurs right after the gear shift form 2 -> 3. 1 -> 2 is pretty smooth, but 2 -> 3 is followed but jerkiness pretty consistently now.

Two days ago the car was 99%. The suddenly it just went to crap like over night.

Do you know if the fuel pump recall has been performed on your X5?

https://static.nhtsa.gov/odi/rcl/201...6V746-7192.pdf

RECALL CAMPAIGN 16V-746

I did a search fairly recently for any recalls. According to the site my vehicle has no more. They did the EGR and both airbag recalls. But apparently that’s all that shows up for my vehicle. Was there a recall on the fuel pump for a 2008 X5 3.0?

Something I just realized, if I’m accelerating lightly, and the shaking starts, the moment I put the shifter in sport mode the shaking immediately stops. There’s no change to RPM or gear. The shaking simply stops. That to me is leaning towards not a transmission issue but some other issue. Very strange! What do you guys think?

"This Recall Campaign involves F07, F10, F12, F13, E70, E71 and E72 vehicles produced from May 2006 to
July 2011."

Not sure where you checked, but if you look here: https://www.nhtsa.gov/vehicle/2008/B...DR/AWD#recalls you'll see all the recalls for a 2008 X5. You can also put in your VIN number to check specifically for your vehicle.

Hard to tell. When you hit sport mode your RPMs should jump as the trans drops a gear. So things are changing in the DME and the EGS that could be masking the problem.

If you drive in 100% sport mode, do you have the same shuddering issue?