There is a ticking/tapping noise on my 2016 Ram 1500 Big Horn 3.6L pentastar V6 with 136,456 miles what could be the issue and how much will it cost to fix.
It is likely that your valvetrain (lifters, rocker arms, and/or camshaft) is worn out. Very common on those engines. If that's the actual cause it will likely cost a small fortune for a mechanic to repair it, depending on just how much damage there is.
https://www.allterrainautocare.com/blog/pentastar-tick/
However, there are other things that can cause that kind of noise. We really can't tell for sure from here, you need a good mechanic to find the actual source. (Not a dealer or chain shop, but a good independent mechanic.)
You could elect to attempt repairs yourself if it turns out that the problem is caused by worn rockers or lifters:
https://www.youtube.com/watch?v=Jhl04daysZU
https://www.youtube.com/watch?v=XkrwxVVcjsg
