91 voyager stalling

I am hoping somebody can help me with this problem fast! Due to the fact I am trying to sell this van soon.
My 91 voyager 3.3L AWD is having some issues under the hood. I will start it in the morning and everything is fine unless I turn it off and try to start it right away again. Then it will have a hard time starting and when I do get it started it will not idle properly and eventually die. If I leave it for 30min approx. it will start up fine again and run great. I am wondering if this is a bad fuel pump or crud in the fuel filter, I know the fuel pump has been changed in the last 5yrs sometime and I don't want to replace it again before selling it, if I don't have to.
I was thinking this might be an electronic problem ex: bad battery, alternator, ignition system? Any other idea's would be great. I don't want to sell a van that runs only half of the time.
Thanks!

check your air filter, make sure it's not dirty, it could possibly be a fuel pump, those usually are some of the symptoms of a weak pump, but I would first check that air filter.