So one possibility is that there’s vacuum going to the EGR when there shouldn’t be. That could be the result of something like a faulty EGR solenoid, or vacuum hoses that are improperly routed.
So you can experiment by temporarily taking the EGR valve out of the equation. Disconnect the vacuum line that goes to it, and try driving the car without it. If the car doesn’t stall, that’ll be a huge hint.
Then you’ll have to track down the cause and fix it. You don’t want to leave the EGR disconnected, because the EPA fines for that cost slightly more than a four-year college education.
But that’s a reasonable place to start, Sarah. And if that doesn’t work, maybe your son can sell the car for $4 and recoup most of his money. Good luck.
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