Is there a way with OBC to read oil pressure. I suspect a oil delivery issue. You may see telltale with the oil pan off. (something you can reasonably do on the 8: have to remove the CV axles on mine).

Also: when you re-attach the stiffening plate be advised they are held on with single used torque to yield bolts. You can reuse them sensibly if you use half the torque angle. Preload to 60 N·m then turn 45° vs 90°. In testing they fail after about 3-4 full tightening processes.

I have yet to work out the exact values partly because I'm upgrading to larger bolts that achieve the same grip at normal torque (unlimited re use). But as I retire my old bolts I plan to do more destructive testing to make some determination on a decent compromise between throwing out $120 worth of bolts and throwing out the function of the aluminum plate (stiffening the entire body of the car)

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)