2003 Jeep liberty 3.7 miss bad injector p203 p0303 p0304 p0354

I had never seen a bad injector before this one very rare to me its a 2003 Jeep liberty 3.7 engine miss wouldn't go away, customer had already tried everything that oreillys suggested but cylinder 2 and 4 would miss, I suspect bad injector and confirmed it with and old tool like from the 90s, to fix the other miss it ended up being bad coil driver in ecm, new computer and NEW INJECTOR. fixed now runs great.