Recently upgraded to direct drive with a new stock hotend. Since upgrading I have been seeing rapid temperature swings well printing (octopi graph looks like an ekg readout). So I tried a pid autotune and after my machine would start to heat up for a print the graph would look good but then I would get a thermal run away error. This happened when printing form octopi or sd card. Ultimately I had to do a factory reset any advice on how to get this printer back to where it was before the new hotend?

Edit

After much tinkering and fighting I have mixed and matched all old and new parts and the only one that constantly caused the issue is the heat element. Though I don’t know what exactly the issue is. As far as I can tell it should be working.