Electrical Inaccurate or Erratic Fuel Gauge This could be caused by one or even a combination of three things.
Body and Exterior Trim Finding Interior Color Codes Location of the three digit numerical code and translation here
On Demand Video $2.99 Battery Connection Troubleshooting and Maintenance - On Demand Video Extremely critical on later cars with on board computer systems
SVO / Biodiesel Diesel to WVO / SVO Conversion Fuel Starvation List of possible causes and remedies for hard starting and loss of power
Fuel Delivery 1986 to 1993 Diesel Engine Fuel Heater Leaking in Engine Compartment This is a very common problem on the 602 and 603 diesel engines
$39.75 W123 Sedan, Coupe and Wagon Instrument Cluster Serrated Rubber Seal - USED Fits ALL 123 1977 to 1985 240D 300D 300TD 300CD 280E and 280CE - not perfect see notes
$79.50 Automatic Transmission Shift Rod Bushing Replacement Tool Kit - New Bushings Included For LATE MODEL (70-73) 108 109 and ALL 114 115 107 116 123 126 201 124 129 and 140 chassis 1968 to 1995
$12.95 Transmission Shift Rod Clip Removal and Installation Tool For all 108 109 114 115 107 116 123 126 201 124 129 and 140 chassis 1968 to 1995
$118.95 OM 603 1986 to 1987 Garrett T3 Turbocharger Basic Overhaul Kit Only for early six-cylinder turbo diesel engines with the Garrett turbocharger.
$36.50 Early Models Rear Differential Axle Seals - Set of (2) - Small Diameter 45 x 65 x 11 ONLY fits those models in the description - but make sure your rear end has not been changed.