Year and model of your vehicle?  I’m not mechanical, so I might get the wording wrong, but I know there was a problem with ignition/plug wires failing due to heat and thus causing misfires on Ford chassis. We have a 2021 Southwind 35K, which was supposedly manufactured after the defective wires were found and no longer used. However, it turns out we had those defective wires in our unit. Two failed resulting in the check engine light and lots of misfires. Once the wires were replaced, everything was fine.