2012 ram #5 lifter noise faults under load.

2012 Ram - Lifter noise-poor gas mileage when under load and #5 cylinder misfire - Sorry. New to this. I put the info in, but apparently, it disappeared. I tried to reply to you, but it started me all over again, so I resubmitted a better story. Everything I found for my truck with the 5.7 Hemi leads me to other's with the same problem and that is the #5 cylinder misfire Code P0305 and the results of other's research is that the roller-lifters wear out and gouge the cam. Another answer was broken valve-spring. I was hoping it would be something like coil packs and spark plugs. Those, I can do. I'm getting too old to do the others. So far, in my mind, I can pay a shop $3500 plus to fix it, buy a remanufactured engine for $3500-$4500 or just go and buy another truck and have a monthly payment for the next 6 years. I'm just stuck on what to do. Any ideas on how I can find the real problem without a shop soaking me? Thanx,