hi guys took my car to a garadge to be done but he is going to have a proper look 2moz but he said he has taken a plug out and it has burned the plugs and he doesent think its the head gasket but what could this bee

 

Burned the plugs? what colour? White? Grey? Black?

It's quite important that you give FULL info if you want a diagnosis from any experts on here. Any smoke from the exhaust? What colour? It using oil? Water? Any oil IN the water? Water in the oil? Down on power? Missing? If so, at what revs, or all the time?

So far, what you are describing could be piston rings gone, under fuelling, det, and probably a host of other things too.