any one no about them and what they do

They connect the camshaft with the valves and open and close the valves.

On the MPi, the tappets act on the camshaft, they are hydraulic and keep the required clearance.

well how do i sort them

They are just one part of a sequence of mechanical components that control the opening and closing of the inlet and exhaust valves in the cylinder head. They are made so that they should automatically adjust their own length to fit correctly and take up any wear in the valve opening sequence. They do not normally need any maintenance.

I think you will need to give more information as to what it is about the tappets that needs sorting. Has the engine lost power, started to smoke or consume oil or become noisy and rattly? What's it doing that has you worried?

well its very noisy yes lost of power any rattles so any help would be great