Seriously about to blow my brains out.
 

2008 X5 3.0 si Active Steering

I have done some extensive maintenance on this thing and I am now faced with a vibration or shudder that is almost non sensical.

Plugs, Coils, Air Filter, Vanos cylinders, Sway bar links, Full Tie Rods, Front Thrust arms and bushings, Wheel Balance, Alignment, Belts, Battery, Pulleys.

At above 80mph I have a shudder/vibration. It lasts ONLY from 80-90 mph. 80-85 with the AC on. I have a slight vibration when making right hand turns at those speeds, that leads me to believe that the control arms or bushings are on their way out but I dont think thats the cause of the constant vibration.

It comes up when I am pressing the accelerator when Im about to head up a hill or even a slight incline. If I let off the accelerator the vibration is gone and everything leading up to 80 is smooth as silk, No shuddering or vibration. On flat roads its as smooth as glass if I am easy on the accelerator after 80 mph, moderate acceleration its there, full its gone.

Last week after some spirited driving I got a CEL for the Exhaust Vanos with the AC on and it went off and hasnt come back. I don't have my scanner at the moment (Its evaporated into oblivion) Whats driving me crazy is that I get no indication that there is anything wrong below 80 mph. Mat the gas down and she takes right off. Gentle acceleration and shes just fine. The only thing that I get on occasion after driving and the car is up to temp is an idle stumble/fluctuation upon restart and that lasts for a few second and everything is fine.

My gut is telling me I have a vacuum leak.....somewhere. I just don't know. Any help or guidance would be very very very much appreciated.

Wheel bearing possibly?? I had my X5 in 3 or 4 times, the dealer did not want to change the wheel bearing because they were not sure that is what it was...I brought it to a different dealership, and we took a chance by changing it, and it went away (we changed rear passenger wb)!!! that was a happy day, as the droning between 70 and 85 miles/hr really wore on me...

That was in the waaaay back of my head and what I was hoping it wasnt. Ill throw it up on a lift on Monday and check back.

Your description leads me to believe its a fuel or combustion issue as it only occurs when the accelerator is pressed. Possibly low fuel pressure, clogged filter or injectors? The "going uphill" issue also points to possibly a fuel delivery problem. Good luck.

Im Meeting with my Indy on Monday to pull the injectors and also check the front wheel bearings. I just picked up the bearings and the injectors got delivered today. He is as stumped as I am knowing how I take care of my vehicles based off my description.

When i read your thread title, i thought, holy crap, my Missus is seeing another person!

LOL

I guess NOT your lucky day? :cool:

Bent wheel(s) or unbalanced tire(s)?

EDIT: I noticed you listed it above, just not sure if that's what you already checked out or just brainstorming.

Well I never got into the shop Last monday, Im going this Monday. I bought the front wheel bearings and am going to explore engine/transmission mounts as well. I had my husband on the throttle last night while it was in the driveway and there seemed to be more movement then I was comfortable with.

Figured it out. Lower Control arms/ball joints. This is what I dont like about the E70. Upon visual inspection everything was fine. Truck is back to smooth as glass @ 75-90 MPH.