Help required 05 fabia vrs nearly cuts out when letting off throttle

Hello all I am doing the usual I am new help me please post. 

I recently brought a 05 fabia vrs it hasnt been well looked after and had a few issues which I have been sorting but I am now stuck with this problem. 

At a standstill if I rev the car up to 4k when I let off the throttle the engine sounds like it's about to cut out/missfire then it recovers and idles fine. The car has had the egr deleted and I believe it has been remapped!

One thing I am struggling with which I think maybe relevant is how does the throttle work? It doesn't have a throttle body and the symptoms are like a sticky throttle or dodgy idle control! 

Any help at all would be most appreciated! 

Chris