I have a 1998 ML320 that I bought about 10 months ago. It ran great when I first got it, but about 3 months ago it started running a little erratic. It was chugging a little bit and my gas mileage dropped. Recently, it has been having trouble starting and staying running. Sometimes it will start on the first try and others I can try it 4 or 5 times with no luck. I am thinking that it may be a fuel delivery problem. Any other ideas out there?