I have got a 340 with f7p engine conversion could anybody help me on how to adjust idle speed please

what fuel system is it running?

The standard injection system with ecu

There's no adjustment of idle speed, it should idle correctly if everything is present and correct. What is it actually doing?

It idles fast on tickover

Could be a number of things. First thing I would check is that the idle air control valve takes it's air from the main feed to the throttle body, not a separate filter. It has to have some vacuum on that feed.

Ok thanks will try that first

does it drop below what you state is fast idle if it does then while engine is running pull one plug off at a time round the throttle housing if there is a change in engine behaviour this means that the sensor is working so try that its quicker