I have a 2000 Civic EX D16y8 5 speed that recently had a head gasket replacement earlier this year. I have this weird problem that I can't figure out. Randomly during idle, the RPMs will get stuck around 1700 and the car surges really bad. If I try to drive the car while this is going on the car will jerk/buckle really bad in first gear and for it to stop I will either have to give more gas or shift to 2nd gear (Sometimes it will jerk bad 2nd gear). I do have a Cel light P0505 although (IACV is new) P1301/P1302. So far I have replaced the IACV and the TPS. I did find out that the mechanic didn't do a valve adjustment when he replaced the head. Could this be the issue? I've seen older posts with similar issues but no fix. Video link below.

​​​​​​

 

Please see attachment for some instructions on idle issue and misfiring. However,
Manual recommends resolving the idle control before proceeding on the misfire as
On the TPS though; as far as I know, the OBD reports throttle position and I wonder if the TPS was changed due to guesswork or the obd actually reporting the throttle position out of spec, the spec being "approximately 10%".
Manual calls for probable vacuum leak after eliminating coolant temp and throttle position sensors in the case of a high idle speed.