Patsy, I don't have an answer, rather a question. My 80 SD does not have this idle knob. What changed between 79 and 80. What controls my idle, a computer?

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1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
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