Cheers guys

So far i have found the following:-

A nozzle clog
A tube clog
AND a gear clog ( fillament jammed in the motor cog)

I have cleared all these but am still getting the pulsing.

I have tried the filaments i have i know are good in both extruders but this left one still a no go.

Does anyone know if one of the screws behind the heat sink is a tensioner