I have a 1990 740 with 200K miles. It runs fine at 10 MPH and above and when warm. However, cold starts cause very, very rough running for anywhere from 5 to 10 seconds, then all of a sudden the roughness goes away. During the rough cold starts, if I give it alot more gas, it can actually stall, but if I lightly tap the gas pedal it keeps running and then it is fine, except that it shakes and rattles at idle when in gear, but does not stall. I have taken it in for servicing and will be doing so again in a few thousand miles, but am trying to determine what is causing this problem.