Hi to all who will be checking this post. My user name is Nijat1 and we own a 1998 MB S420. We bought the car from the owner at a cheaper price due to the fact that he didn't take good care of it, mostly it has cosmetic stuff, however we do have a Check engine light that reads multiple O2 sensor failure and Cylinder 2 and Cylinder 4 misfire, we tried checking the coils by switching all of them from left to right and that didn't work. We also bought new new spark plugs for cylinder 2 and 4 that were bosh +4 premium and that didn't work. We got to check now the wires, fuel injector, and compression, if anybody has any ideas please write them down. Also the model we have has a 5g tronic(5 speed) but we are really confused about the lifetime fill liquid for our transmission, some say change it, others dont, our only argument would be that it would ruin our transmission eventually.