Renault Clio 1.2 16v Engine Swap issues.

Hi everyone, im after some help here is my situation;
I bought a renault clio 1.2 16v 53 plate with a snapped timing belt, I decided to buy a new engine from a local scrapyard which I went and inspected and saw running perfectly fine. I got the engine and while it was out I changed the timing belt, water pump and clutch kit. I fitted the engine to the car and swapped the ecu from the old in order for it to match the key etc. Now to the problem, I start the car and it will misfire, it sounds perfect if I rev the vehicle, Then if I let it idle it will misfire badly and the electronic incident light will come on, it will then increase the revs to around 2000 rpm at which point the throttle will not respond very well. The things I have tried:
-I swapped the coil pack with the spare
-I have swapped the engine wiring loom with the spare
-I have swapped the throttle body with the spare
again I cant be sure these spares are working but there is no reason why not.
We are getting a demo diagnostic machine at work tomorrow for a week or so in which I will borrow tomorrow night and see what codes it can pull up.
Any help would be great Thanks