Cylinder 4 misfire - Bank 2 system too lean

After six months of my car occasionally hesitating upon acceleration and jumping a bit when idling, it finally kicked out an engine light code indicating cylinder four was misfiring. Two days ago I took it to my local trusted mechanic. I left it with him for about ninety minutes. It appeared he did a thorough investigation. He explained there are multiple causes and levels of repair regarding a cylinder misfire and that unfortunately, my problem goes to the deepest level. The engine. He said he replaced the coil pack with a used one before ordering a new one to see if that would fix it and it did not. He lifted the cap and had me listen to clicking noises going on in there. Sounded like an electric charge type of clicking noise to me. He said that was never anything you wanted to hear. Very bad! He further explained I was only getting 60 lbs of compression. Bottom Line: "Your car is terminal."

Strangely, he indicated he had another customer in this past month same car, same problem at 150,000 miles. Same diagnosis. I live in a small rural town. Is this a known problem with Ford 500 or just a coincidence? Or a misdiagnosis?

He said it would require an engine replacement to fix it and he could not recommend I do that at this point in the life of this car. He drove it and said the transmission also sounded "off" to him. I agreed. I have only driven this car for three years and have always complained about the extremely whiny engine.

He told me I could continue to drive it until it quit but he would not recommend taking it on a road trip. Only around town. Ironically, it has driven perfectly the last two days, leaving me baffled and confused about what to do.

I am basically asking for a second opinion. Is it possible my mechanic missed something easier to fix other than an engine replacement or should I consider this a complete loss? I am really bummed as it does no sound like I can even use this car for a trade-in. Nor am I financially wanting to assume car payments on another used vehicle with its own unknown problems. (Fixed income!)

I was so happy to see you guys out here in cyber world, so graciously offering advice to those like me who truly have no clue. Many thanks!