I'll answer too since I'm having the same issue
any all, manual tray or paper tray, any type of media.
The paper is getting to the fuser on time, did a bunch of 1/2 way tests and looked at different times where the paper was. It's 'like' the fuser is running slow even though I don't see how it could.
On the one I'm working on, the paper is oriented right into the fuser, not crooked. The print is exactly where is should be but since it gets the 'late jam' all stops and the print never gets to be fused of course.
I myself have taken the fuser apart twice, it looks perfect. I re-greased the sleave just to make sure, it turns perfectly by hand or if I'm watching it while working in the printer.
Now here is my question, is it for sure that in a non duplexor N model, that the fuser only runs at one speed? When it starts to print (you know how these printers are kinda noisy?) you hear the paper come up, then you hear things get a bit louder like normal that rr rr rr rr sound, almost like it's trying to kick the fuser up to a faster speed but never does. A tech told me only the D model does this?