I have had my Astra in and out the garage for months now.   
fault: intermittent driving and it feels as if it’s bad fuel or fuel not getting through. 
go into 1st gear and the acceleration feels as if it’s chugs as I drive. Go into 2nd ok for minute then same problem.  
had timing chain changed/spark/new Cat also. plugs/valves all done.  
They tested the fuel pressure and it was fine they said. 
Engine management light comes up every 2 wks or so.  The code is related to camshaft position.  Picking car up again today and they can’t pin this down. The mechanics say they have tried everything.  
anyone had similar weird problems. Or can enlighten me on an option for the problem. 
 

Thank you for any input. I don’t  want to get rid of my car, unless I have too. 

Have you any update on the car problems ?

No update, I’m driving the car and it’s still intermittent and comes on about once a week for a full day or two. The mechanics who changed my timing chain say they can’t spend anymore time on it. As they can’t find problem? 
I don’t think it ever was the timing chain. But once they had taken taken apart the engine they had to go through with changing it..  

I wonder if it's as simple as just being the timings sensor fault. I've heard of people having to change these out after the timing chain being done and even having faulty brand new ones... don't know if that helps at all.