1996 if it has a mass air sensor, it also has an IAC Idle Air control, they go fairly often. If your mechanic has a decent scan tool, he can check the IAC cycles against the desired IAC cycles. If not, I have all of the tools to do it, where are you located? I specalise in driveability and vehicle electrical. And deisel
Edit, I see you list a location as Mashpee, Im in yarmouth