When cold its okay but after a minute the idle gets really erractic it goes up and down. I do not have a rpm tach on the civic. Weird part is. its fine in drive reverse and everything except gets erractic only in nuetral and park.

I first thought too increase the idle but i dont htink its adjustable on the d16y8 (throttle body faces up)..

What do you guys think? I was thinking maybe map, vacuum leak.? but its not throwing any codes (cel)

 

vacuum leak..

 

sounds like a vacume problem