I noticed my vacuum line is missing from my egr (or is it evap?)

maybe
https://cimg7.ibsrv.net/gimg/www.s2k...ad67394ad9.jpg
this is the issue? Or maybe the prev owner deleted it?

Update - Potential Solution

Okay - so my earlier EVAP post - total dead end. I guess the EVAP is venting to atmosphere... its a non issue.

I took apart my IACV - I mean actually took the whole darn thing off. The first time I did this (months ago), I just unbolted from the intake mani and peaked inside, moved the valve with my finger and just assumed it was fine just because it was easy to wiggle. NO - you gotta take this darn thing off completely. Then follow the Billman post on this (https://www.s2ki.com/forums/s2000-un...k-iacv-943369/).

You MUST separate the motor - this will suck probably. The prev owner clearly tried and FAILED. Even after buying the T20 tamperproof tool set - no luck. I took it into my apartment and used a hand dremel to make a flathead screwdriver grove. Then you can access the spinny thingy on top - like Billman says, spin that thing like top. I mine would spin a little, then suddenly get stuck. This might explain why I would SOMETIMES have idle issues! Depending on where this darn thing gets stuck, your IACV is stuck closed or open or partial! That would explain my car going into limp mode every time I took my foot off the gas. Also, if it is stuck open, you have unmetered air entering the system that could cause you car to run crappy.

I will put another post up in a few weeks to confirm if the issue has totally disappeared.

GUESS WHAT?

My issue returned :(

Since i snapped a header bolt the other day and my valve cover was leaking like crazy, decided to have a local shop do a valve adjustment.

they said my car is running super rich and that just might be the issue. Since Jeff Evans has been shut down by the government, planning to do a remote tune. Any suggestions?

Okay... so i got the below done:

- vc was leaking, so new seals
- valve adj, but they said they were fine
- RETUNED... biggest thing imo

The car is running MUCH better. Got my low gear boost by gear limits dropped... lets see if I can break into 120's trap speed finally.

UPDATE:

So within days, the issue resumed. Yes... $1k later, still there. Also, it got so serious that I almost got crushed by oncoming traffic at a major intersection.... had to honk my horn like a maniac to slow down traffic!

At this point I asked my mechanic to drive the car until he experienced it. They normally would fix a small item, drive it for 10 min and declare victory. This time... after fixing a leak and relay, they decided to drive the car to lunch. The car completely stalled out and refused to restart immediately. This sent my mechanics into BEAST mode.

Turns out my MAP sensor was "failing". Not completely failed, just performing poorly. Swapped it with a new one and now all is well. (200 miles so far)

IACV thoroughly cleaning does it for me
 

Had an issue with my 02 s2k since I brought it back in 2019, issue is random hesitation at low rpm range, idle would drop worrisome when I blip the throttle in neutral when engine is warm and car starionary. I didn't pay much attention as I thought it was the inheritance of low torque Honda engine, once pass 4k it is all power baby! However, every so often the car without warning will give me a sporadic jerk like I lost all power for a fraction of a second and at time it jerk multiple time very quickly and then back to normal. After read the forum, MAP and IACV is what I want to give it a shot, and to isolate the fix, I only clean the IACV, it looks not bad but it definitely has black carbon coating in the IACV so I soak it with seafoam and brush clean 4 times until the solvent came out clear, the 2 sections closest to the firewall are connected, make sure it is clean in between. Now it idle so well and no longer have the rpm dip til engine shake when I blip throttle, thank you everyone!

Had this issue with my ap1 engine, idle would drop to 500 ish also stall on occasions, however i had to replace my engine ( due to a spun bearing)and did an ap2 swap. With the ap2 engine and ap2 ecu perfect idle, so i decided to swap ecus and use the ap1, guess what the idle dropped to 500 ish, the same as the ap1 engine. I swapped back the ap2 ecu and idle went back to normal. Root cause of low idle in my case was the ecu.