Hi DavK26,
I've just joined the forum so don't know if you've managed to sort this or not.

If not, Is the extruder body plastic or metal ?
If plastic please check carefully for cracks (mine had one which allowed it to flex).
I recently replaced my extruder with a dual geared on and it did make a difference. They are quite reasonably priced on Amazon now. If there is a problem further down the the tube the dual gears won't help.

Anyway, hope this helps you.

Cheers,

Andy