If is dieseling or sometimes called "run on" where you turn key off and engine chugs, not firing on all cylinders, but not shutting off, the problem is excessive carbon build up in head and pistons causing carbon hot spots.
This is abnormal for a FI car, since fuel supply is also shut off, so in addition to above, you may have leaking injectors.
I would start by running a couple of cans of SeaFoam in tank. It will help cleaning carbon from engine.
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Wednesday, October 28th, 2009 AT 8:34 AM