Q: stalling on 2002 Ford Explorer Sport Trac

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When the truck is put into park, it stalls. It will start right back up. It has 201k on it. The shifter seems very loose. Is it a bad cable, need of a tune-up, vaccum problem or something else?
(1) Answer
had this problem with sister in laws sport trac about 3 yrs ago, hard to remember.
On the top of the engine a little to the left there is a rubber elbow that connects 2 metal lines, about the size of your index finger, some sort of blowby. burnt oil sets up in the bottom of that elbow and deteriorates the rubber. it fails and creates a vacuum problem, causing truck to stall and run rough. dont know about the shifter problem.