Rendering Miissing Part

i got a mesh where when i used the texture mode in 3 D viewport
some part of a model is missing see pic
if i used the solid mode it’s ok
so this is only in texture mode
but this does not seems to show in the final render ?

is there a way to correct this ?

Thanks

Try first going into edit select all (a key) and hit ‘ctrl’+‘n’ and select recalculate normal outside. In textured mode it doesn’t show faces with the normals facing away.