#1. Remove air filter housing.
#2. Get a smooth flat board to cover the intake.
#3. Inspect the throttle linkage, visual and manual, push - pull- jerk, look for binding - jamming - interference contact, under dash and hood.
#4. When you are sure the linkage is free moving, get an assistant to help with the next steps.
#5. Stand over the intake with board ready; but watch the throttle linkage at the injection pump.
#6. Have assistant start car.
#7. Do not hesitate to seal the intake with board, if it accelerates wild = over 1500 – 2000 RPM.

#A. Turn off with stop lever.

#B. Turn off with board.

If you feel confident to do this test, it will give you and us a lot of information.
Have a great day.

__________________
ASE Master Mechanic

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D

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