W124 E420 - Help Diagnose this please

[AtlBenz]

1994 E420

This is what happened.

Car stalled out after a perfectly normal day. Idled erratically upon restarting it. Stepping on the accelerator (at idle) causes hesitation. but if held at 3000rpm, runs smooth. Strong foul odor, and a touch of black smoke out of exhaust. After a few attempts, car stared and ran normally and was able to drive 70 miles with no signs of a problem.

Car has 139K. Throttle actuator was replaced. No check engine light. No problem when starting cold. When warm, car still starts instantly.


any idea what the heck could be going on?