S 500 Mercedes problems

Can anyone tell me if they have had any problems with the 97 S 500. And any problems with assistance from Mercedes.
My engine light has been on almost the life of this car, I continued to get it checked at an authorized dealer RBM and they told me evertime I went in it was just the gas cap. Now after warranty I take it in again and its a 3500.00 repair. This is an outrage to me and Mercedes corporate will not even give assistance on this. The problems with this car are the problems that were found at 40,000 miles and I cannot understand why the same problems keep occuring. The problems are;

purge valve
code for right rear 02
throttle actuator
srs version coded improperly
coded improperly

at 40,000 they were
instrument allumination
purge pressure censor 40,553
FUEL VAC LINE 47,061
vacum line
evaporated fuel line closing 47,062
and more recently)63,000 purge valve
charcol canister filter
bridge looking purge valve


I also had problems with my 93 500 SEL and again no help from corporate. The problems with that car were transmission gone around 60,000 mile s, ($3800.00)evaporator hose gone at 58,000 m ($4000.00)not to mention the srs bag sunk in for no apparent reason and of course no help from Merc corp.