Been at the dealer 3 times this far for a knock on startup and ticking coming from left side of engine....Left side Rockers replaced, valves replaced and tapets. Being told now it?s the fuel injectors making the taping sound? Contacted Chrysler fca customer care, obviously dealer and fca working together. I?m being told the continuous knock and taping is normal. My truck has 13k miles, synthetic oil only. Sounds like a Diesel engine. Any suggestions???