Check all the vac lines.It could be your boost protection valve. "Or BP Valve"
It is the little unit on the the firewall with vac lines going to the alda and the
intake manifold. My SD would not go up hills for @#$& !!! I took the BP valve
from my friends 300 CD and bang.... It was a whole different car. If you know
someone with the same turbo diesel engine, just switch it with yours. You
will tell right away if that is your problem. Also the BP valve on a 300 D or CD
looks a little different then the SD's, but it will work the same. Jay

81 300SD Black 132M "Sold"
81 300SD Blue 139M "Sold"
81 300SD Blue 246M
82 300SD White 202M
84 300SD Burgundy 168M "New"
85 300SD Gray 267M "New" "Has damage to the rear"
84 190D Red 111M "New"