Code 300!

[Russell Arrigoni]

I have a 2008 Ram 2500HD with a 5.7 liter Hemi engine. The check engine light is on and I need it to pas inspection next month. I know the code indicates a "multi-cylinder misfire" but the truck starts right up and runs great. I've replaced the plugs, fuel pump, and the crankcase positioning sensor but the light stays on and the code 300 still reads. The truck does not leak coolant so I don't believe it's a head gasket problem. Any ideas?
Thanks,
Russ

 

[LoneWolf3574]

P0300 is a general misfire code, it is not specific to any cylinder. How long after you reset the CEL does it take to come back?

 

[ViolentMouse]

p0300 is a fun one. I usually start with long term and short term fuel trims.

Too lean causes it. Too rich causes it.

Ever get it sorted?

 

[Hesabiggin111]

I'm having the same code on a 2008 1500 with a 5.7 the freeze frame on my code reader says it happens before it's fully warmed up and it happens at a low speed. It says most common repair is replacement of spark plugs next is o2 sensor but when I pull up the graff's it doesn't give a graft for the EGR it just says EGR error. I'm no mechanic and this code reader is smarter than me by far but I'm not wanting to throw money at my truck when I'm not sure what the EGR error is about. One last thing I pulled a few spark plugs and every one of them the gap was around .065-.070 instead of .045 is this telling me spark plugs are the problem? Maybe some of this will help with your problem as well.

 

[LoneWolf3574]

I'm having the same code on a 2008 1500 with a 5.7 the freeze frame on my code reader says it happens before it's fully warmed up and it happens at a low speed. It says most common repair is replacement of spark plugs next is o2 sensor but when I pull up the graff's it doesn't give a graft for the EGR it just says EGR error. I'm no mechanic and this code reader is smarter than me by far but I'm not wanting to throw money at my truck when I'm not sure what the EGR error is about. One last thing I pulled a few spark plugs and every one of them the gap was around .065-.070 instead of .045 is this telling me spark plugs are the problem? Maybe some of this will help with your problem as well.

Yes, replace your spark plugs. I'm assuming you ran them for a long time as the worst of my copper plugs (the recommended for the 5.7L Hemi) was worn 0.008 after only 28,000 miles.

 

[Hesabiggin111]

Yes thank you lone wolf it was spark plugs I just bought this truck a few months ago and it's in great shape came with all the work records and everything but my guess is the dealership or wherever it was taken pulled a fast one cause I was given a folder with a million receipts so the previous owner tried to take good care of the truck. Thank you it runs great no check engine lights.