Help finding episode: car fails after stopping at the grocery store?

Years ago, there was a super-puzzling story on Car Talk that I’m trying to locate. Any help appreciated. It went something like this:

The caller says that he stops each day at the grocery store on his way home from work. If he buys milk that day, when he gets back into his car, it won’t start. But if he buys soda instead, the car starts fine. I might have the milk & soda wrong, but that was the basic idea: the car’s behavior changed based on what he bought at the store. I think Click & Clack initially didn’t believe the story was real, but then they solved it. (The answer is at the end of this post. Don’t read it if you dislike spoilers.)

If anyone could please point me to the story, that would be marvelous. Thank you very much.

Dan

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*** SPOILER ALERT ***
*** SOLUTION FOLLOWS ***
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Milk & soda were located in different parts of the story, and depending which one the guy bought, he spent a different amount of time in the store. The car’s problem was influenced by how long the car sat after being parked.