00 Civic. D16Y7. I have high cold start rpm going 1500-2200. It stays at 1400 at traffic stop. When I start moving, it sputters at 1900 while accelerating. I give it more gas, and it doesn't sputter.
The IACV was cleaned out. Code 14 - OBD2 wasn't checked yet. Not much vacuum leak I can find. Back pressure could be low due to a hole in the resonator pipe - it's at after cat & o2 sensors on Y7. I don't have FITV.
I overheated severely eight months ago. Blocking throttle body lower port lowers it to 600-650. I didn't change the idle screw, since the idle used to become normal after warm up to be 750 at driving. This park+driving idle problem happened after HG job recently.
Coolant was bled.

 

Thanks everybody who advised me to fix the car!
The past six months have been nightmare, but finally I can drive with not a single problem!
I can earn a living and go to school without worry anymore!
I'm having this limitless joy at this moment that I finally got back on the road!
The first thing I came up with tonight, after the HG problem and Idle problem were solved was Honda-tech. You guys rock, and really the Civic people!