How much of a problem is it to let a misfire from a bad ignition cylinder go? I've been driving it with a misfire in cylinder 4, but not sure if I'm going to damage it. 1999 Toyota Landcruiser w/312K

if you do lots of high speed driving it will wear it faster. Just driving around town though it normally doesn't ddamage much if it runs decent and doesn't buck. though it will wear out the cat faster