der,

I've had a similar problem in a '79 300SD. It was very intermittant. Not the low power for minutes but the on and off power for a few seconds when engine was warming up. It felt like an old distrubutor gasoline engine with bad points.

I never found out what it was as it always cured itself before I could try to anaylize it. Very unDiesel like, I've never seen another Diesel engine act like that.

P E H