Buick/Olds: Non-Start, buick skylark, driving time


Question
This is a 93 Buick Skylark, 3.3 V6; at time after being driven for a while, let,s say 1 maybe 2 hours , unit will not start, dealer can,t find problem, note cold starts are not a problem, please can you help?!!!

Answer
I'm going to need some more info from you if you want me to help.
Is it a no crank OR cranks but wont start?
Do you know if you are loosing spark or fuel or both?
Does it restart again after it cools down? If so how long?
Do you notice any running problems before it wont start?
Does it stall and then not restart?
Does it sit for a little while after driving and then not start? If so, how long does it sit.
Is the 1-2 hour driving time around town or highway?
Give me as much info as you can to help me give you the best advice.