I just purchased a 2000 Honda passport it was fine the day I bought it then had ecm issues. I replaced the ecm the egr valve mass air flow sensor TPS pcv valve. This doesn't happen everyday but it does happen quite frequently I will start the car it will start right up idle goes up and down not drastically but between 500-750 then I will put it in gear and the car shuts off. Like I said it doesn't happen everyday but when I do drive it the idle drops pretty low it never stays the same. I'm at a loss I don't know what else to do I went to a shop they did a diagnostic on it and said my speed sensor was bad which I changed and it still does it. Any help would be gratefully appreciated.