Chevy S-10 doesn't always start

Maybe someone here can help me. I have taken my 2001 chevy s-10 to the dealership and they can not figure out what is wrong with it. My truck will not always start up right away and can take several tries to get it to start. The dealership says that everything associated with starting is fine and they thought the ignition switch was causing the problem so they changed it but it is still having the same problem. I did have an alarm on the truck but was also told that may be causing the problem so I took that out but again that did not help.

When it does not start check for low fuel pressure or lose of spark.
Is the problem cold or hot or other?
Is the security light saying on when it no starts?
Did they check for codes past or history or present?