Fiat 1.2 Hunting / Revving poor idle FIXED SOLVED

Filing the mating surface of the manifold fixed the uneven idle this engine was experiencing, I suspect the car had ran low on coolant for one reason or another and this is what caused the block to get so hot and allow the manifold to melt and pull the fasteners through. Thus compromising the seal of the inlet port gaskets. I'm currently waiting for a new metal coolant pipe to arrive so that I can finish this repair off and draw a line under it. the coolant pipe was rotten and started leaking whilst I was diagnosing the problem. something else to keep an eye on with these engines, it runs along the front of the engine underneath the exhaust manifold and connects to the back of the water pump.