Intermittent P0304 Code At Idle, 2010 3.0L VVT GDI V6

[sdhow]

I'm getting an intermittent P0304 DTC at idle that goes away upon acceleration. New coils, plugs, timing chains, sprockets, phasers, complete top end, VVT solenoids and sensors, etc.

I can erase the code and it will run fine for awhile, but then returns after a longer drive and drop back to idle. Shut it down and restart and the CEL/Stabilitrak service goes off. Could this be a faulty ignition coil driver or an ECM programming issue? It runs perfectly between the intermittent episodes, which leads me to believe it's not the GDI injectors. I really don't want to mess with the DI high pressure injector rails if that's not it.

 

[Tico007]

Coil issues tend to be a Japanese car problem. I suspect it’s the fuel injector acting up. Bad spray pattern, orings. Get a remanufactured one off eBay. They clean them up. Give that a try.

 

[sdhow]

Got a new OE injector online, but I'm having a bear of a time getting the injector rails back in place. Read somewhere that GM actually changed the head design to add a groove at the bottom of the injector port to allow for tip insertion.

Is this true? If so, how do you get the injector back into the port on the earlier models? I was looking at the factory shop manual...says "Remove head assembly"...

 

[Tico007]

Did you lube up the orings? A dab of grease from a grease gun is OK.. Do not use carb or brake cleaner on the injector O-rings. They will swell and you will never get them back in the hole.

 

[sdhow]

It's not the fit of the injector tips once they're in the ports, it's getting the tips to line up with the port opening itself. It's the angle of the tip being compromised by the fuel rail coming in contact with the opposing intake port. GM obviously never designed these injectors to be serviced without the removal of the heads. Designed to be assembled, not to be replaced.

 

[sdhow]

Got the injector rails back in, but still had the same P0304 code. Took it to the dealer for diagnostic before dropping $700 on a new ECM. Was told "Yep, it's the ECM!" After a new ECM, the diagnostic and the programming ($1,200), it's still doing the same thing. Now they're saying there's fuel in the oil and it's a defective (new) fuel injector...but it's doing the same thing as it did with the old injector.

WTF???