Car aparrantly OK before battery ran down. With new battery (Not fitted by me) car will not start or run unless foot is on gas.

It will rev freely if you boot it but if you try to maintain steady revs it surges badly (Like On/Off/on/off IYSWIM) If you alow revs to drop it will stall.

Fault code for throttle body P155? (but cant remember full number Fool for not writing it down! )

Cleared code to see if it would "Reset" but made no diference. Code did not return despite symptoms persisting.

Launch will "Drive" the throttle body (But only full closed or full open, IE Launch can not test for subtilties in the action))

Live data seems to be good for both gas pedel and the throttle position sensor as far as it goes.

(IE The output on the throttle pedel varies smoothly with position and the feedback signal from the throttle body varies smoothly with position when the plate is moved by hand with the engine on but not running)

BUT I didnt get round to scoping it due to my own auxiliry battrys getting flat (Mobile-end of long day!)

The surging seems to be as a result of the throttle plate switching between being fairly open and clamped shut, it will not hold a position to provide a smooth idle or light throttle.

Now, I am thinking that this is most likly to be the vauxhall throttle body/ECU issue and the best solution will likley be off to the dealers with it.

But, I would like to know exactly what it is that happens to these??