Vauxhall Omega 2.2 CD Automatic Petrol

Im in dire need of some help!

My car as developed an unknown fault, the car as now been in the garage for two weeks and the mechanics are unable to find what is wrong. The symptons are as follows:-

1. Engine doesnt fire straight away, turns over for a few seconds before starting.
2. Lack of power when accelerating, almost crawling going up hill.
3. Stalling.
4. No Kickdown.

Theyve changed the cam sensor, the electronic throttle unit thingy ( cylinder shaped unit with a metal plate on it ),  also found the wiring loom under the dashboard was broken as it had dropped and was rubbing on the steering column, they also changed the petrol filter thinking that it maybe clogged. They are now in the process of stripping the gearbox.

The diagnostic tool shows that there are no codes.

I would appreicate any help anyone can offer.

Gezzie