Strange Jolting from 2005 s60 2.5t

Hey there. i cannot find anything online about this.

My 2.5t s60 had a problem a few weeks ago, it had an 'engine service reuqired' light on, at 30 kmph the engine would jolt/skip noticably. i let the car sit for a 3 weeks while i did some other work such as pcv and coolant flush and waiting for parts. It disapperacred after that and ran liek a dream.

Recently while driving. i made a maneuvour in the (heavy) rain where the car hit the limiter and lost traction to all wheels essentially doing a 4 wheel burnout. aftter i got home and turned the car off, i left ir overnight and came back to that same problem returning.

any ideas???

summary.

Car jolts subtly as soon as i hit 30 kmph in every gear. Returning issue.