P0300, P0306 codes #6 cylinder misfire (1 Viewer)

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Nov 24, 2003
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Getting ready to tear into the engine this weekend and see if its the wiring harness or the #6 injector causing this fault code. Looking for any advise on this tear down. I ordered an injector but are there any other parts required for this, gaskets, seals, etc? I need to get them on order today so I can get them before the weekend. Any help would be greatly appreciated.
 
If you are planning to remove the upper intake, you should plan to replace the gasket that goes between upper and lower intake. I posted in someone's thread how to remove the upper intake in 30 minutes for injector work, it's how I replaced my leaky injector. You may also want an EGR gasket and to replace the two coolant hoses that attach to the intake since you are all up in there.
 
I'm starting the same project tomorrow. I ordered the injector, a spare o ring set, the gaskets for the upper intake plenum. I'm also going to do the PHH, coolant bypass hose and fuel filter while I'm in there, since they will be way easier to access with the upper intake off.
I soaked the EGR studs and the big EGR nut with Kroil, since they're pretty rusty. I'm planning on pulling the upper intake without removing the throttle body, so I didn't get a new gasket for that.
 
I'm starting the same project tomorrow. I ordered the injector, a spare o ring set, the gaskets for the upper intake plenum. I'm also going to do the PHH, coolant bypass hose and fuel filter while I'm in there, since they will be way easier to access with the upper intake off.
I soaked the EGR studs and the big EGR nut with Kroil, since they're pretty rusty. I'm planning on pulling the upper intake without removing the throttle body, so I didn't get a new gasket for that.

That's the way to do it. Just remove the EGR studs and leave it in place. You'll need a special drive socket for that, any autoparts store has a cheap set of them. There is enough room to get the intake out without removing the EGR valve assembly, it's tight and takes a little bit of force, but it is way easier. Leave the throttle body on too with all it's cables and just swing it up out of the way once you have the thing loose. No need to drain the radiator either in my opinion, or at least only drain it part way.
 
Check the harness at the ecm. I did what youre about to do and it ended up being a bare wire hitting metal. Also did spark plug tube seals, phh, fuel filter and valve cover gasket.
 
sbman, do you recall the thread where you posted the how-to on the upper intake? I looked but didn't see it.
 
It was here:

#6 injector replacement question

I basically followed the FSM, but skipped removing the throttle body and the EGR choosing to just remove it's studs instead so that the intake could move vertically with the EGR in place. I had to pull slightly on the EGR, it has a little give to it. I also chose to slightly bend the brace that runs down lower on the engine instead of removing it, just bent it slightly back to put it back. Also easier because something was in the way of the lower bolt of that support bracket.
 
So, got the #6 injector out and it ohms 13.7 so I'm thinking it is good. Inspected harness behind egr and it was in good shape. Re-wrapped it with cool tape. I was really hoping the injector would ohm bad and I'd know that was the problem. Getting ready to put it all back together and see what happens...
 
Bad injectors will still ohm out okay. They often get plugged and won't spray.

Your best bet would be to swap the injector with a different cylinder and see if the problem moves to that cylinder or stays. But that requires removing the rail and potentially all the other injectors, which opens up a new can of worms. In that case, it would be good to send them to a cleaning service and ask that they test them first. If it's clogged, you probably don't need to go after wiring. If not, at least you'll know it's good, and that all of them got cleaned.

Good luck with it!
 
If you pulled the injectors, you really should send them for servicing... You've done all that work and to just reinstall seems a little crazy.

cheers,
george.
 
I'm going through the exact same thing. In the sake of time, I ordered injectors from Rock Auto. After I return the cores, the cost isn't very much more than having them serviced, and much faster. I'll be installing them Wednesday.
 
Well, it was most likely the injector. R&R'd it and wrapped the harness really well.. When I fired it back up all codes were gone. Running well and no codes back as of yet.
 
Didn't have the time available to send out the injectors for servicing but that would have been awesome...so would have been changing the phh while in there but can only do so much in one weekend.
 
Signing in to confirm the cyl.6 misfire can be caused by a bad injector. Visual inspection including removal of EGR confirmed that coolant had been leaking from the heater pipe - it looks like I failed to tighten a hose clamp after I repaired the head gasket. There was coolant residue on the valve cover and around the No. 6 injector, which was wet. After compression test passed, I pulled the throttle body and managed to get the number 6 injector out. Checked for resistance and no reading. It should be 13 ohms. Checked another injector and it checked out ok. So it looks like the No. 6 injector just got gooped with hot coolant to the point that it gave up.
 

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