I was experiencing something similar a little while back. The wheel would kick violently for no apparent reason, although my G25 has worked fine for many years.
It was around the time I fired up my new rig and switched to Win 10, but I cannot say for sure why it started happening. It was more noticeable in GTL than it was in GPL, but both were uncomfortable to drive..
If I recall correctly, I made multiple small adjustments to the FF settings until I managed to dial out the random spikes. I think I posted for help and copied someone else's settings to try and solve the prob. Once I had quelled the beast I made the settings universal for all games.
Maybe I should try the FFB2