hi. i wanna ask my car is running on daihatsu L2S 12valve N/A with 850cc block with 1.0cc piston. my engine problem now is it always constantly dropping RPM to 500rpm when its was cold. sometimes it drops till engine is dead. i have to drive it for almost 15mins to make sure it was steady. but it will sometimes happen when the engine is hot also. i have changed my plugs,distributor,map sensor and ignition coil but the problem still persist. can someone please help me? thanks..