Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1981 Plymouth Arrow Pickup Base, Automatic TransFACTORY OEM SERVICE PROCEDURE
Vacuum Throttle Positioner: Adjustment
- Start engine and accelerate to about 2000 RPM. Verify throttle positioner operation. Throttle positioner must withstand hand pressure. Manually open throttle until engine speed reaches approximately 2000 RPM. Loosen lock nut and adjust throttle positioner until it just contacts throttle lever.
- Release throttle lever, then slowly adjust positioner until a sudden drop in speed occurs (over 1000 RPM). At this point, continue adjusting positioner in a decreasing direction for an additional 1/4 of a turn and tighten lock nut. Accelerate engine to approximately 2300 RPM and release throttle. Engine should return to normal idle speed.
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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