I would also suspect GP's normally, but it was doing it when warm then there may be other problems. Could be anything from bad fuel to low compression. Don't you hate answers like mine. :p

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'10 Chrysler T&C Stow-N-Go White. Grandpa's ride.

'13 Chrysler 200 Touring Candy Red. Grandma's ride.

Age and cunning will always over come youth and vigor.