Catalyst efficiency below threshold. (The catalytic converter may be failing.)
Glow Plug/Heater Cylinder 4
# 3 cylinder misfire.
Trouble code P0301 means: Cylinder 1 Misfire Detected
#3 cylinder misfire.
Do didn't say which engine you have. The trouble code PO420 is telling you there is a catalystic converter not doing it's job. We need to know which engine and what year you have in order to determine which cat is at fault.
Trouble code P0300 means:Random/multiple cylinder misfire detected
No such code B0265. P0265 however means = Cylinder 2 Injector Circuit High.
Trouble code P0144 means:O2 sensor circuit high voltage(Bank 1 Sensor 3)
Trouble code P0420 means:Catalyst system efficiency below threshold (bank 1)
You need to obtain a troubleshooting chart for that code. If I recall, it has to do with the Evaporative system.
Trouble code P0171 means: Fuel Trim System Lean (Bank 1) Trouble code P0300 means: Multiple Cylinder Misfire Detected
Misfire on cylinder 3. Get it fixed asap so you don't mess up your catalytic converter.