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Injector removal write-up? ( P0300 / P0304 codes)

701 Views 5 Replies 3 Participants Last post by  05ctsav
I have an 05 CTS-V hardly driven (basically sits 77k miles) and started to get flashing check engine light. Pulled code and reads P0300 and after driven awhile it’ll change to P0304. I changed the spark plug and coil in bank 4 and swapped wires. Still no change. My next step is to swap injectors but I am having a hard time finding any “how to” vids or write-ups. Can anyone help me or point out any resources. Any additional help on the codes and misfire also greatly appreciated. Thanks in advance!
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Do this when engine is cold and by then fuel pressure will be down

There are 2 mounting bolts per fuel rail to remove from intake manifold
Disconnect the wiring connectors for the wire loom for that side's coil and injectors
You only need to lift rails high enough to get end of injectors out of intake, so should be no need to take fuel line from tank off the left rail

You will have to pull/yank up on the rail to get the injectors to come out of the intake
You will need some towels there as some fuel will come out
Pull the top of injector out of fuel rail
Each injector has a O-ring at both ends so make sure they still on injectors and not have come off

To install the ones you swap to prevent the O-rings from rolling over is put a drop of oil on each O-ring first
Watching that the end of each injector is pointing to the opening of intake set the fuel rail down, making sure injectors seated and O-rings did not roll and pinch.
And wiring connector of injectors pointing the correct direction as they were before taking them out

Tap each end of both rails to get injectors seated, remount the bolts but do not over torque them
Once all wiring connectors are plugged in, turn ign key ON, but do not start engine
This will get fuel pressure back up to rails (about 58 PSI) and check closely at all injectors that there are no leaks
Perfect, it’s a lot easier than I thought. I’m glad I do don’t have to remove the fuel line. Thanks for the fast and thorough reply. Greatly appreciated!!!
Thank you both for the additional tips and info..Hopefully I can find time tomorrow or the following day!
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