P0171 Ford - escort zx2

Question

I have a 1998 Ford Escort zx2. its a 2.0L DOHC. I used my obd2 scanner and it read p0171 on the generic test and on the KOER test it read p1127 in which the case is an o2 sensor. I have already replaced my MAF sensor, temp switch, thermostat, starter, battery, fuel pump, but i do know my catylitic converter is rattling the platnum ib the inside... any suggestions would help. I have worked on everything on my car personally, the except fuel pump was done at a shop.

Answer 1

check for intake leaks first, if not intake leaks are found, also if your spark plugs have not been replaced its a good to replace them

replace the oxygen sensor on bank 1 sensor 1