Its a B21A1 90 SI. It has recently started to endlessly stumble at idle, and it seems like it even might be stumbling under acceleration also. For a problem like this where should I begin? It overheated recently because of a bad thermostat, i replaced it, flushed out the cooling system, checked the oil and coolant for oil and coolant, its not smoking, and it warms up ok. So I'm kinda thinking it might be something on the Throttle body, or maybe the dizzy timing. Any ideas?