Hi, I have a 2003 dodge Dakota, 3.9 engine, automatic, rear wheel drive. 174000 kms. The problem I'm having is a p0303 cylinder 3 misfire, even though I have replaced everything I can think of that has anything to do with ignition, including oxygen sensors. Compression test results are all good. Some days it won't do it but 95% of the time it does. Has anyone ever had this same problem? Any help would be appreciated and maybe slow down the greying of my hair.

 

How about the fuel injector, have you tried fuel injector cleaner?

 

In that case I would go look for a flat cam lobe on the mechanical side...
Check to make sure it is getting the juice...
And like Iowan said. Injector....

Note: you can swap some of the parts ad see if it follows, to check to see if the component is faulty or not...

Keep us posted..

Just my 2 cents

 

Could also have a bad valve spring

 

So True..

 

Could be a bad valve guide, had it happen on a Pontiac V8 twenty years ago. Sometimes the mis was there then it would be fine, finally it was more consistent and diagnosable.