Hey, I have a 2001 dodge ram 5.9L. For a while I have had a O2 sensor error go on and off, recently I started my truck and it was shaky and not running properly. I drove it for a minute and noticed the check engine light started blinking. I turned the truck off then back on, all shakiness went away but engine light stayed on I checked the error codes and i got: P0300, P0304, P0138, P0455 and P0308. So Basically multiple misfires which was noticeable, the EVAP leak and the O2 sensor. What could be the cause of this? The truck only has 140,000 Kms

 

Also, I have 0 mechanical knowledge, I will be taking it in to get checked, I saw online that it could be bad fuel pump or head gasket. Basically just want to get an Idea, I live in small town and don't have much trust in the mechanics.

 

A misfire can be cause by many things. Spark plugs, the wires, bad fuel injector, head gasket, bad valves, they can be really cheap or expensive.

 

Or a bad plenum gasket.