Hello everyone,

I have a 2016 grand caravan with a 140K miles on it. About 2 months ago I had p 219a code which is air fuel imbalance in bank 1. Other than the light in the dashboard, there was (and there is) no serious issue such excessive fuel consumption or loss of power, etc. Only thing I have very small idle issue, like the indicator in the rpm goes up and down very minimal (it is difficult to notice). I replaced the o2 sensors of bank 1, map sensor, and checked the vacuum lines, air filter etc. The problem did not go, so I replaced the fuel injectors of bank 1 and bank 2, so I changed 6 of them. P219a code went off but now I have p219b code which is air fuel imbalance in bank 2. I am gonna go crazy. Did I mess something? What might be the problem?
The car has an engine ticking sound for along time which I believe is a common lifter/rocker arm problem for pentastar engines. Could that be a reason for air fuel imbalance?
Thanks for your opinions and suggestions.