All,

For all those that have helped me resolve my idle problem on my 98 civic 5 door hatch vti.

Summary.

Was reving at 1500, running rich, hunting when warm at 2500 - 3500, throwing no error codes.

I replaced he throttle body "did not work"
Cleaned out IAC "did not work"
Replaced various sensors "did not work"

OK so I took to Honda to get them to check, they said "your ECS is not reading above 50c, that COULD be your problem". In fairness they were great if not a little slow to look at my car. They wanted around 250 to replace this sensor plus temp sensor and re-fill coolant, clean throttle body etc" they also said "this may not solve the problem"

I therefore went and got a used sensor from the scrap yard "ECS" as soon as I replaced it, problem solved

So there we go. Again thanks everyone for your advice and help over the last month