05 Dakota P0300
 

Hello Everyone -

My '05 Dakota, 3.7 V6, recently had the top half of the engine rebuilt. This includes all of the following:

Replaced right side head, all valves and all springs
Resurfaced left side head and replaced all valves and all springs
Replaced right side valve cover
Replaced all gaskets along the way
Replaced timing tensioner and guides

This was all done as the right side cylinder #1 exhaust valve spring broke while driving down the interstate and destroyed the head and valve cover in the process.

After completing all this work every few days the check engine light will come on with P0300 and sometimes P0304. The P0300 is the most common and I have only seen the 304 once or twice. I have checked all the coils and the plugs. I have even replaced all the plugs to make sure. The timing is dead on and the compression and fuel pressure checks out accordingly.

It seems to only happen after it was warming up in my driveway for a few minuets. It seems to be driving normally but I can barely notice a small miss / rough idling when it is not driving. I don't seem to notice it while driving.

This problem really has me stumped and I can't seem to figure out what the issue is. Does anyone have any ideas what this could be?

Thank you for any help you can give with this issue!

you may very well have a intake leak some where, grab a bottle of water with a misting head, and while the engine is running, lightly spray around the intake and see if the engine noise changes,