My K Series will not accelerate.

Hi... Can anyone help me... I have a Freelander 1.8 K Series and it's not working again...
Just had new head put on and now it will not accelerate from tickover, it just splutters and goes to stall..once you get past the first 500 revs from tickover its OK.
Have changed fuel filter, dis cap - arm and all leads. I've also put injector cleaner through and now changed throttle sensor but it still not working....
H.E.L.P anyone

A couple of things come to mind, is the cam timing definitely correct or maybe a slight air leak on the induction side say from the inlet manifold gasket or tubing from throttle flap etc.

thik you need to check timing and that all the hoses and wiring looms are securely plugged in.

Also check that when the doors fell off, all the wires & check straps etc sheared off or you could be dragging em behind and creating loads of drag..