My 300E has had a hard start problem for quite some time now. From cold, it takes about 5-10 sec. of cranking and pumping the throttle to get the engine running. Unless I rev the engine a bit at startup, it will run rough for a short while. Once running, however, the engine runs very nicely... for a while at least. The hard start issue returns if the car is turned off for more than about 30 minutes. In fact, it's often worse if the engine is still somewhat warm. Any thoughts?
Once the engine is thouroughly warmed up, another thing happens... the engine begins to run rough at low RPMs when driving. It is most noticeable when acclerating from a stop, and is especially pronounced when I punch the throttle from a stop. The engine smooths out as the RPMs climb in 1st gear, but the stuttering returns when the transmission up-shifts and the RMPs drop again.
Any thoughts?
Thanks so much!
Mika