Just got a 83 300sd, it runs great, no smoking, etc. On steep inclines it will barely takeoff. There is a big hill pulling out of my driveway and it pulls it about 5mph. When it gets to the top the car takes off strong. I have tried it when the motor is cold and hot. I dont believe the boost is low. On my Buick Grand National, when I have had a problem with low boost, it blows smoke badly out of the exhaust. The 300sd has a new injector pump. I was thinking that the people who installed it, didnt adjust everything right. I can push the pedal about an inch before it starts moving the actual rod going to the injector pump. I think it might need adjusting to get the slack out.

Thanks
Bass