The problem is very inconsistent. Sometimes it dies, and the security key light comes on. I have to pull over, almost immediately, and shut it down and remove the key. When I start it back up, this usually corrects the problem until it happens again. Other times, it will stall, or bog down, buck real hard, and then keep on running without any other problem. Sometimes the check engine lights comes on and the above happens and it goes off. Other times, it does it without the check engine light ever coming on at all. Any suggestions are GREATLY appreciated.