"Service Engine Soon" light & fault code
 

Greetings all.

About a week ago, "Service Engine Soon" light comes on; @ my local service center (not a diesel shop), the fault code indicates "misfire on #4".

It was reset and remains so for about a week. Just reappeared.

Worrisome?

Solutions?

--Bryant

Bad injector or a short in the wiring.

Wild Bill, thank you.

I can fly the hair off of a $19million Army helicopter but I truly know very little about diesels, much less the Duramax. If you've time, I'd really appreciate your thoughts on my questions below:

Is this an issue that should be checked out by a GMC dealership service dept or should I look for a recommended non-dealership shop?

Why is there no other "noticeable" in how my truck runs?

As there is no noticeable difference to me, am I hurting the truck by running it?

If it is the injectors, do I change all of them? Just that one? Just one bank/side?

And....should the injectors be replaced with factory or do you recommend and "upgrade"?

--Bryant

first get the balance rates checked on the injectors and find out exactly what code it was so we can help you better.

could be a bad injector. the wire harness really doesn't get loose on the lb7's at all

The code is P0304.

ok, Do a balance rate test, find somebody with a tech II, efi live, or a programmer that can check that, injector #4 is whats setting the code off.