Where abouts is the car?

It could be a number of different things causing that issue, best to go back to basics and examine all the foundations from the start

If in Sydney or nearby I can help

I guess you need to work out if it's originally an lh2.2 or 2.4 setup. Does it still run a maf sensor? Maybe post a pic of the engine bay

    timbo I'll post some pics tomorrow, pretty sure it's running a map, and wideband o2/lambda, and I think it is only used for fuel control.
    It's running a coil and distributor, not sure if this is relevant, I am fairly intelligent but new to this sort of stuff.
    I have the microsquirt manual and the tuning suite, but I am not willing to touch anything yet until I know more.
    Am probably going to get a proper tune done when I have spare cash, but until then I want to learn as much as possible.

    High idle could be as simple as a vacuum leak.

    Check the idle air hoses for splits etc.

    Check what kinda ignition setup it has, as maybe the tacho has never worked after the engine was swapped . We can advise on what wiring to check once we get a look at what setup its got.

    The descriptions I’m seeing of this car & it’s current problems make me suspect that with a little bit of work (and prolly some knowledge from redblock experts) you can likely get a car that’s like a billionty times nicer than it currently is! 🙂

      So under the throttle body was the black plastic tweaker, which I tweaked, and the in park revs have been bought under control now it seems.

      Is there a chance that the throttle position sensor may be out if whack, if I understand things it's an ohms reading that I might need to check.
      If so I need a multimeter, so a trip to the tool store as my fluke has had an accident and requires a new screen.

        Sunshine 245 yes that is a possibility, there may also be a configuration in the microsquirt something along the lines of "minimum tps"

        What this does is tell the computer if TPS <1% then enable idle control.

        If the actual TPS is out (lets say 2% open), then the idle control circuit won't enable because its above the minimum tps threshold

        also just thinking out loud, check the part number on the TPS itself

        I wonder if the previous owner used an lh2.4 on/off or changed it to an 850 style potentiometer

          May I suggest you give Jake @ West Coast European in Bayswater a holler, he looks after our 142 and 245, used to be at Perth Swedish. Highly recommend!

            You need a tuner that knows MS

            6 months later

            Is the Microsquirt only running the fuel side of things? not the sparks too?

              Sunshine 245 yeah but what fires the coil, the microsquirt or the stock 240 ignition controller?