2005 3.7 Jeep Liberty # 4 injector problem

I am assuming that you have a Jeep Liberty w/ a 3.7L right??

Have you ran a dry/wet compression test yet??

How many miles and what year is yours??

You could have a dead cylinder or very weak one…

That could be an important clue to the cause. Where did you add the Seafoam? To the engine oil?