Got a bit of an interesting one!

Car once going at speed above 20/30 mph engine runs brilliant strong

However sitting idle if you rev light or moderate, fine, but a heavy blip of the throttle like sudden heavy pull away or heavy prod when stopped and in neutral I get a misfire sometimes backfire then it's fine

Unless it does it when heavy pull away sometimes it will keep misfiring till I let up on the throttle

Also worth noting my lack of proper fuel cap, got an emergency plastic one awaiting delivery of replacement, an issue?

Much obliged for views and questions, I have replaced the coil pack to rule it out!

Fuel cap wont be an issue. Check and clean all sensors, MAF will be a good one to start with, crank sensor too. Then once you have ruled out all the sensors go for other ignition components like plugs, leads ect. But its more than likely to be a sensor of some sort

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might be you temp sensor for the ecu

When my MAF was being a cock I had similar symptoms, are all wires in one piece?

sounds like early symptoms of your coil pack starting to fail, that is where i would start and many other mechanics, checks your plugs, plug gaps and leads too

just do it

what do you need to know?

its the sensor thats sitting on top of the thermo stat