The issue for me was a bad MAP sensor. It had a large offset error.Thanks. I follow . Interesting. I will let you know and post some pictures after my exchange of the manifolds. I am really interested in these cracks, because I have a little knowledge about plastic injection moulding. Especially this GRP plastic. It is not the wrong material at all for such parts but if the reason is the welding seam..... I had trouble with welding of plastic parts over months, till the machinery worked right with the right parameters :-(.