Guys, tagal na ng idle drop problem ng civic 96 vti ko,. Pero baka yung symptom na to ang makapagsabi kung ano talaga sira nya.

Here is the situation:
I followed the recommended steps by Honda on how to set the proper idling of my engine (as stated on their service manual: let the engine warm up, disconnect IACV, set idle to 450 +/-50, reset ECU,). I set the idle to around 470 I made sure na the rad fan is not on while I set it ha. So tama naman ginawa ko diba?

The Honda service manual said that the idle should be at 750 +/-50 without AC and 850 +/- 50 with AC (cant exactly remember pero around ganyan yung natatandaan kong figures). Kaso pag start ko ng kotse, yung idle nya is 1,100 RPM without AC, 1,200 with AC. Masyado mataas diba, pero hinayaan ko na lang since hindi na nagddrop yung idle. And sobrang responsive yung change ng idle kapag nag on ako ng AC, meaning pumipitik pataas yung idle ko pag bukas ng AC or headlight.

Then after my 50km trip to Novaliches. Bumalik yung idle drop ng auto ko. Hindi naman nagalaw yung idle screw kasi talagang tinandaan ko sya. I even put gasket around my idle screw to make sure na hindi sya gagalaw. My car is now idling at 800 without AC, and 500 with AC pag bagong bukas ang oto. Pero mawawala yung idle drop kapag naitakbo ko na. Magiging smooth na yung idle after running for 15 mins.

Tingin nyo guys ano na problema nito? Para sakin hindi IACV ang sira nito kasi pag bagong reset ang ECU ko, nagwowork sya ng maayos. Definitely hindi TB, IM cleaning ang solution kasi nagawa ko na sya 3 months ago.

ECU kaya ang sira? Vacuum leaks? Ano pa bang pwede? Thanks! Sorry medyo mahaba.