KV6 P0306 Misfire

Hello, I have a 2003 Freelander KV6 Petrol. I am getting P0306, P0304, P0301, etc. 78,000 miles.

After resetting the codes, it starts and runs fine for 5 to 10 minutes. Then when accelerating away from a stop it throws the errors. At the same time the Fuel Status on my scanner changes to OL-Fault (open loop fault).

I have new plugs, inspected coils for arcing, wires, etc. Fuel pump has a new filter.

It runs strong and well until the error pops up, then runs rough (obviously because its misfiring)

Any suggestions?

Thanks for you time, in advance.

Actually, after sitting for 30 minutes or so with the ignition turned off - the Check Engine Light goes out.

Plugs are clean, no oil or water visible. No water in the oil in the engine, no oil in the coolant. Engine runs quite and STRONG.

I don't think it has any problems with compression. No tell tale knocking sounds of slipped cylinder liner.

The plugs are dry.

I'm not losing coolant. No indication of coolant loss.

I already put a new fuel filter in.

Just the misfire codes.

Thanks

P0306 Cylinder #6 Misfire Detected

P0304 Cylinder #4 Misfire Detected

P0301 Cylinder #1 Misfire Detected

Yes, that is what my scanner says.

What repairs are required to resolve the misfire codes?

thank you