Here's another suggestion- - - -install an "idle stop solenoid" It's a device that is used to set the curb idle speed, connected to the ignition switch. When the ignition is turned off, the magnetism goes away and lets the throttle plates fall fully closed. No airflow- - - -no dieseling. Here's one of several dozen examples that are on Ebay today.

https://www.ebay.com/itm/403516468951?

Search "idle stop solenoid".
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!