Mr. Formula

Good morning this is my first post on this forum. I have a 2002 Formula with the 6 speed. It has 87500 miles on it. The problem is that sometimes it wont start. The starter does not engage no clicks nothing. It does the same as if you try to start the manual transmission with out pushing the clutch down. The security light does not flash or anything. It has been to the dealer 2 times for this problem. They replaced the ignition lock. The car ran fine for 4 or 5 days then did the same thing again. It was towed back to the dealer and stayed there about a week. They said they could not replicate the problem. Apparently every time they tried to start it , it would start. I had them install an ignition switch. The car started fine for 2 weeks, then started the same problem again. On yesterday I put in a clutch switch. That did not solve the problem. Any ideas on what the problem could be? Is there a work around for this? I dont want to go back to the dealer. Thanks in advance.