I recently had the top end rebuilt on my 300CE. In addition, I replaced all six injectors, the fuel accumulator and filter. On warm starts the car will crank over and fire quickly for a brief moment and then die. On restart it runs, albeit slightly rough. When I engage drive or reverse the idle seems to drop to around 500-600 rpm and run noticeably uneven. It also feels a bit sluggish off the line. On cold starts is seems to crank a bit long (2-3 seconds) before the engine begins to fire. Any ideas as to what I should look at?