CEL Code P0300

[marshall_308]

My car has been showing the multiple cylinder misfire code lately. The car usually only throws the code when going down the highway, then I will reset the ecu. Then the code won't return for a long period of time then when rps are consistent it will throw it. Motor seems to run good no noticeable misfire at idle, but the car will die sometimes when cold and after I push the clutch. I have been searchin and searchin and seems there can be multiple things that cause this. But what are some common causes? Or any input would be appreciated....

 

[spyderdrifter]

Check spark plugs and wires. Maybe check fuel injectors to see if they need a cleaning.

 

[3kgt2nv]

had the same issue when one of the injectors had a wire break. it would occasionally lose connection when the wires pulled apart.

 

[starfish]

I had the same code at one time.I switched wires,coil,plugs,I even bought a new ecu because the car wouldn't run after a while.It would start up and idle only.I was on my way over to the parts store to pick up a Fuel filter and I noticed that the gas station that I go to was taping off all the entrances.I pulled in and they told me that their tank filled up with water.Their insurance paid me almost $900 for all my parts.So you might just have some water in the tank.If you pull your pump out to change the filter at the bottom,look for water at the bottom of tank.its a long shot ,but you never know.

 

[2gnt99]

Definitely replace or check plugs and wires, check plug gap.

Test the coil pack. A fuel injector cleaner/gas water remover might help. Also, change the fuel filter.

I think that sums up the (cheapest) things that could be causing the code.