Another miss'n query

[Luke]

Hi Folks - hoping you can cut down on my fault diagnosis efforts...

I've got a 2.6 litre 109 Station Wagon. Recently it's started coughing and hesitating when turning sharp left or occasionally up hills from a standing start.

I've assumed so far it's fuel starvation or carb. Checked the sediment bowl and it's clean. The fuel pump filter had a little debris but basically clean also. One possible clue is that when I wait for a few seconds for the pump to prime on starting I can normally hear a tone change - not getting that at the moment. Could it be a blockage in the tank? If so, how can you tell? It's a station wagon so I've had the rear floor plates up but it wasn't obvious (to a dimwit like me anyway..) where you'd check. Through the fuel sender plate? It's full at the moment so I'm leaving that one until it's empty.

I was also thinking carb. I noticed recently that it's not holding oil but I'd have thought that would affect it all the time, not just turning left... I'm still digging up info on that one.

Any help in cutting down the number of straws I need to grasp at would be greatly appreciated!!!

Cheers
Luke