I have the same exact problem with my '99 Rodeo LS. the problem has been on going from 4 months after i purchased the vehicle up until just a couple of weeks ago. I have taken my rodeo to the dealer several times, even opening a problem case number. When I attempt to start the vehicle it will turn over for a fraction of a second and then the rpm's drop quickly until it dies. however, if i keep the accelerator down when i start it, it will stay running. Once I get off the accelerator, it dies. the dealer will do nothing because they can't duplicate the problem because it is so intermittent. i have no answers, but i know how you feel!! i will keep an eye on this thread for more answers. thanks