Hello I have to 2005 Chevrolet TrailBlazer EXT LT 4x4 with the 5.3 L. About a week ago I had an engine code that said cylinder 4 misfire detected I've done what most people I think would have done I ran the usual tests everything checked out fine but I still ended up replacing spark plug wires and plugs, coil pack , injector and installed a new air filter ,clean the EGR valve and replace the camshaft sensor ( which I ended up having a code for that's why I replaced it)but I still have the code coming up after it's been cleared saying that misfire detected on cylinder 4. well now I'm hearing some things about the crankshaft sensor that could be causing this? I'm not getting any code for it ,but no matter what I do I still get the misfire on cylinder 4 detected code P0304 ,so reading up on it I read about crankshaft position sensor relearn procedure. I don't have a scan tool is there another way that I can do this without buying a scan tool or taking it to a mechanic shop? working on cars isn't my life but I do to my own vehicles to try to save money I can't see spending hundreds of dollars on a tool that I might use only once or twice in my lifetime. But also do you think its the crankshaft sensor? after everything I've replaced? is that the only thing that it could be?

 

the crank relearn only needs to be done if the cks sensor is replaced. This is needed to stop false misfire codes at high rpm.
if you haven't changed the cks sensor...a relearn isn't required.
you missed an important step in diagnosis.
if you have confirmed:
-spark
-fuel pressure
check compression with a compression tester.