My 3.8 olds 88 just just stops like turning the key off. you let is sit for half hour and it will restart. Is thire a maginet on the cam in side the timing chain cover?

Start with the simple and replace the fuel filter and inspect the ICM. (ignition control module) A failing ICM will stop working when it get's hot and when it cools off, it will work again and eventually the ICM will stop working at all.

Thank you for using fixya and start with the fuel filter if it has not been replaced once a year or 25,000 miles.