I found with the advent of ASW that the game would feel like it would run in surges, much like you describe. I now force ASW on (Ctrl-NumPad 3) and it seems to smooth it out. I can only guess that the the FPS is dropping in and out of the ASW auto-switching range.
The performance is still atrocious considering the graphics level I have to set it at with a GTX 1080, i7 4770K, 16GB RAM. I still get some stuttering around the place - mainly in cities or complex environments. It is usable but not optimal. (I still enjoy it and waste far too many hours on it)
For me ETS is a bitmlike elite d. A totally different experience in VR. I think the relatively poor performance is due to it running on DX9. Iirc 12 months or so oculus declared that officially vr is no longer supported in vr. I think the devs are currently working on porting their games over to dx11 (not 100% certain so dont quote me).
If this happens i expect performance willcshoot up
Fiat Coupe, gone. 350Z gone. Dirty nappies, no sleep & practical transport incoming. Thank goodness for VR 🙂