Thanks for your insights.

Its a 1979 300D auto trans.

I had the shift lever bushings replaced about 6 months ago, so they are all sound. Also sound below on the shift linkages.

I will see how it behaves tomorrow during a cold start.
And report back in case further insight is needed.

Its just that the symptom experienced did not match the bad neutral safety switch syndromes posted in the archived threads.

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1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD

I agree.

Unless the shaking engine caused enough vibration along the shift rod to make a statement at the NSS. And the NSS itself is beginning to fail and interrupted the starter signal.

The only other thing I could think of is that the ignition module is worn out and unless you keep a good torque on the key, you may lose contact.

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