reading misfire codes on all cylinders. Is there a test for this?

Hello. lol I like the Gas House. That's the truth. Hey I did find a bad valve cover gasket with oil in one of the cylinder tubes. I replaced all sparkplugs and replaced one ignition coil. The p1361(TDC) code went away and p0301 and p0303 went away. The light came back on after she drove it ten miles and now has codes; 0300, 0302, 0304. Those are misfire codes. Could it be that all the ignition coils went bad?

you have the codes,but,is it really misfiring?if misfiring,it could be one or more things.do you have a vacuum leak somewhere?are the other coils bad?valves clearences and timing,compression?is cam or crank sensor bad?egr system plugged?start with simple things first.check all vacuum hoses for leaks with engine running.then check the coils one at a time with engine running.engine running at idle,unplug one coil electrical connector,if idle changes,runs rough,that coil is good.continue to each coil,one at a time.unplug the electrical connector on the next one,if the idle does not change or run rough,that coil is bad.post findings.