740i has a high rev [3000rpm] at start up and stays there

Sticky throttle cable, cold start valve. Does it do anything different at normal operating temperature? At normal temp does it "hunt" run erratically or otherwise behave differently?

You could find someone with a fault code reader to find out BMW charge but an independent might not.

any advise will be helpful thank you in advance for your help

and any advise will be helpful thank you in advance for your help

Many many things but try: split vacuum pipe into inlet manifold somewhere (there's a mass of them and they can get split or damaged from rubbing) throttle idle position switch (mechanical one somewhere on cable - perhaps near throttle butterfly valve) debris in throttle butterfly assembly air flow meter giving false reading (again - grubby? oily? if earlier type or if heated wire type, then a simple failure) lambda probe?

Any running problems - poor power at any part of the rev range?

David

your engine is in safe mode now.....

I think he wants to know the reason for it - and that would be the fault causing the safe mode! What's the fault?