CTML

Being brave, I decided to clean the MAP sensor for a smoother low speed idle. I followed the steps here https://www.s2ki.com/s2000/topic/515...ationsolution/

Now I've put everything back together and did an ECU reset (pulled the fuse out), the car idles stable at 1k at start up but when i put the clutch down to shift to first/reverse it stalls and loses all revs when i touch the gas pedal.

I've got a feeling that when cleaning the MAP ports, a tiny bit of dust has got inside - could this be the cause of the issue or is my MAP sensor on its way out?

Doyal

try applying pressure to the top of the map sensor whilst the car is running, you might have a tiny air leak from the o-ring that sits under the MAP sensor. It goes a bit flat over time, and might not of sealed properly when you put it back together.

I had a similar issue when I changed mine (had to replace the o-ring in the end)

MB

Have you let it learn the idle? Need to let it idle for a few mins.

That or you have an air leak / lost the o ring from the MAP.

CTML

Absolutely nailed it! Thanks!

I replaced the O-ring with a bog standard one, probably used for standard plumping; will it survive under the heat of the engine?