Sounds like Pam's Datsun needs a solenoid adjusted.

Dear Car Talk | Oct 01, 1995
Dear Tom and Ray:
Pam
RAY: I know exactly what it is, Pam. I happen to have gotten my M.D. in B210s.
TOM: M.D. is "Mechanic of Datsuns." And by the way, he got it at MIT: The Massachusetts Institute of Transmissions.
RAY: There's a device on the carburetor that raises the engine's idle speed when the car is in Neutral, and lowers it when the car is in gear. It's activated by a switch on the transmission. The device was put there for emissions reasons, the details of which I don't remember because I dropped out of the MD/PhD program in Datsunology before we got to that course. But I do know that the device (which is called an "idle up solenoid") is adjustable.
TOM: Find someone who's worked on these cars--or someone who has the shop manual--and have him adjust the solenoid for you. Then you'll be able to spend more time driving and less time huddling.
Pam
RAY: I know exactly what it is, Pam. I happen to have gotten my M.D. in B210s.
TOM: M.D. is "Mechanic of Datsuns." And by the way, he got it at MIT: The Massachusetts Institute of Transmissions.
RAY: There's a device on the carburetor that raises the engine's idle speed when the car is in Neutral, and lowers it when the car is in gear. It's activated by a switch on the transmission. The device was put there for emissions reasons, the details of which I don't remember because I dropped out of the MD/PhD program in Datsunology before we got to that course. But I do know that the device (which is called an "idle up solenoid") is adjustable.
TOM: Find someone who's worked on these cars--or someone who has the shop manual--and have him adjust the solenoid for you. Then you'll be able to spend more time driving and less time huddling.
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