this is 1996 Civic DX hatch

D16Y7 with 5 speed - stock everything
it starts right up every time with no issues. Idles fine.

then, problem starts after I drive for 10 minutes..(5-10miles). no idle issue when driving, but once I come to a stop and the RPM drops to around 200-300. Engine shudders a bit, but does not stall.(sometimes it stalls, but starts right up) Once it does this, I have to rev it to keep above 200-300.

and just few days ago,
the CEL popped (P0131)...so i replaced o2 sensor (DENSO), and light went away since..
but the problem is still there even after replaced it

so far i have...
cleaned IACV
cleaned throttle body
replaced O2 sensor (primary
replaced spark plug (NGK)
adjust throttle cable
adjust throttle idle screw

i heard vacuum leak can cause this problem, but i don't see/hear anything unusual.

searched all over, i've found a lot of people with same issue, but none of them came up with answer..... out of luck, need help desperately..

 

Sorry for that, having the same problem...

 

hopefully we find answer here.. and end this.

 

I would start checking TB Gasket, IM Gasket and then check TPS. When did this problem start happening?

 

Does the d series have a fitv? If so take it off clean it and adjust the screw in piece to obtain correct idle might take a couple tries of turning to get the correct idle.

 

vacuum leak could be the issue.. I had some sort of evap issue before and I had the charcoal canister replaced. Car honestly ran fine before, but after the replacement, I got this idle issue and stalled out a couple times too. It eventually fixed it self, but Im not sure what the root cause is. Could be evap related.. but idk..