changed headgasket put it all together according to service manual best I could I triple checked the timing chain marks and the black links and all that sht.
at first it wouldn't start then it started and ran for 2 days I did valve adjustment then took it for a test drive and it was studdering on acceleration very bad almost dying during throttle tip in
idles rough.
didn't find any vacuum leaks either

after the test drive I let it idle and after about 10 minutes idling it just shut off like it lost ignition. didn't stumble just stopped running like when you turn the key off and didn't start back up

I plugged in the scan gauge and theres no codes and everything looked good.

it had a cooland blowout on the headgasket but otherwise had no problems before that

I never worked on s2000 so don't know any specific tricks or other crap that these cars are sensitive about.
I did get the service manual and everything is torqued to spec and aligned to spec as far as I can tell