Can someone point me in the right direction. I have a 2wd Cosworth which starts on the button, no noises, rattling etc. runs fine when giving it a bit of throttle (when stationary, cars off the road at the minute), but as soon as you let of the throttle it stalls. Starts back up fine again. Just stalls once taken foot of throttle.

Is it likely to be the idle valve or tps??