What did they say was wrong?
They told me that cylinder 3 was imperfect(small scrape on cylinder wall) which was causing the loss in pressure. they replaced the intake valves, both heads and cylinder #3. I am not all that savvy when it comes to the mechanics of a combustion engine so they did other stuff as well but I don't really know what, just happy that my Jeep is now running like it should. I am the 3rd owner of this Liberty and both previous owners also tried to get the issue solved, only took 4 years, 97000 km, about 800 $$ in needless repairs and countless visits and phone calls to the dealer, personally I think that they just got sick of me.