Can someone please help me with an issue I have with my Mk3 1990 Ford Orion 1.6i (EFI)

the car idles high around 1200rpm. It doesn’t matter if the car is started from cold or has been driven for some time, it remains the same.

It’s sometimes hesitant when accelerating, it stutters like it has kanagroo petrol. It sometimes cuts out when I change to either second or first gear from a higher gear. The revs drop to about 600rpm, the engine sometimes cuts out, sometimes doesn’t.

I’ve changed the spark plugs, put fresh 99ron fuel in her and cleaned the idle air control valve. I’ve checked all hoses for any cracks.

The exhaust has a slight leak. Not sure if this would make the engine idle high or cut out.

Im really stuck now. Any suggestions would be much appreciated. Thanks