Repair needed? Cheap but Honest Mechanic Needed

What is your question?

I have a 2005 Merz Benze S500. The car rides fine for about 25 blocks. Then, when I get to a stop sign or light, the car almost dies. When I give it gas, it almost dies. I can't go up a small Hill. One Mechanic has charged me 3 times, saying it was the Distributor Cap. That has not work and I will not go back. Someone told me, it could be the Fuel Filter. The only 3 Benze shops I know of, I don't trust. What do you think the problem could be? Do you know of any reliable Mechanics in the Inglewood/L.A. Area? Should I go the Mechanic and tell them to change the Fuel Filter, or should I just allow them to tell me anything,,, could be the Problem???