Misfire on all cylinders

Wife has a 2012 Prius and was starting out on a trip this morning. Made it 10 miles and car started to shudder all the sudden so she pulled over. Codes are showing misfire on all cylinders randomly. Starts fine will idol but with constant misfires and shudders harder if you hit the gas. No coolant loss. Head gasket replaced 20k ago as well as EGR cleaned, new pvc valve, new plugs etc. the only thing I can think of is I removed the very back heat shield that’s underneath the car last night as it was coming loose but looking under the car I don’t see any dripping fuel or anything damaged wires etc. any thoughts on what it might be?