Rebuild time

[Chamberpains]

PM Unilevers or MommaBurt. Get it sorted out remotely while you have down time. Even out in the field. If you can turn your phone in to a WiFi hotspot and you have good solid reception you can do it anywhere your phone picks up good reception. It'll only take an hour at most probably quicker if you dont have a slow j1708 connection. Most trucks came with faster j1939 connectors. My international did not.

Your intermittent blow by could be bad programming. It could be running poorly on a cool day and not hot or your at a higher altitude and you ECM doesnt know it. There's a lot going on in them these days. You need to know its right 1st. Before you jump down many wrong expensive rabbit holes.