1999 Mercury Marquis • V8 • 131,000 miles

My 99 mercury marquis just started do this. I turn it over and it starts but runs very roughly then dies. I go to start it again and it turns over but doesnt start, then I go to start it again and it starts. Then it is ok till I go to start it again. Any ideas? Fuel filter? Fuel pump? If I go to a auto parts place can they diagnose this on a device? Thank you
July 29, 2011.

Try cleaning the idle air control valve, EGR and PCV valves and see what happens

Jul 29, 2011.
The auto parts store can't diagnose anything. The can read stored trouble codes but that is not a diagnostic and they often can't even do that right.

Jul 29, 2011.