We are having a similar problem with our C220. We bought it a few months ago, it's a 96 with 93000 miles. We started having random no starts, so in reading off the message board everyone recommended changing the OVP relay. So we did and it started every time for a week then it started having the same problem again, it also stall on us once. We have no idea what could be wrong. We have been told to check the fuel sensor unit or try having the wire harness replaced. I talked to our MB dealer and was told the wire harness alone without tax and not including installation was a $1000. So we are hoping someone out there may have some other suggestions to try first. This is our first Mercedes and we love driving it, so we can't wait to get it fixed.