2nd gen 2.7 with valve problem

I recently acquired a 2008 access cab, 2 wd, manual transmission and long bed. 145k miles. It was running rough, flat miss on 2 cylinders. The price was very reasonable and figured I could dump an additional $5k into it and still come out ahead. One cylinder was a coil problem. The other (cylinder #4) surprised me. Zero compression. Compression tests indicated a leak on the intake side. The original owner is no longer with us so I have zero information about the vehicles history. Haven’t pulled the valve cover so no clue what’s going on.
Any ideas what could caused this? Assuming the head is good, do I just replace the bad valve(s)?
Thanks

 

Not unheard of for the 2.7 to have a leaky valve, do you have a borescope to look in the cylinder and see what things look like? There's even some relatively inexpensive ones now that have a side camera or mirror that allows you to see the valves.

 

Thanks Dm93 for your response and suggestions. I don’t have a bore scope att. I’ll probably just wait till I can remove valve cover though that will probably be a while as a am having some medical issues that greatly control when and how long I can work on it.
Thanks and take care.