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Discussion Starter · #1 · (Edited)
I need help I am getting misfire codes on PO302, PO304 PO305, P1399 I have switched coils put in spark plugs Did a compression check all right around 180PSI and seem like Cylinder #2 is the faulty one even after switching coils and changing spark plugs While running i have discconected coil in cyl 2 and doesnt affect the engine rpms like the other coils do
Thanks in advance
George
 

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Use OEM NGK Platinum spark plugs. Most cases this is a faulty coil(s). To a lesser degree it could be a faulty injector or a loose/bad electrical connector.

The P1399 code is a temporary code related to the cylinder misfiring codes P0301 to P0306.
 

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Discussion Starter · #3 · (Edited)
misfires

i thought i took care of the bad coil by switching and i did put in nkg OEM spark plugs gapped at .044 the wires to coil all get battery voltage when key is on. Also wouldnt a faulty injector cause a injector code to be included with the misfires? a P0171 or something like that?
 

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P0171 would be a problem with the fuel pump, fuel line, fuel filter, fuel pressure regulator, O2 sensor or EVAP Cannister Purge Valve.

You don't have any other codes than the ones mentioned, right?

I am attaching the troubleshooting for your codes if that helps but 9 times out of 10 it is a bad coil.
 

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2011 Odyssey LX, 120k miles
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I need help I am getting misfire codes on PO302, PO304 PO305, P1399 I have switched coils put in spark plugs Did a compression check all right around 180PSI and seem like Cylinder #2 is the faulty one even after switching coils and changing spark plugs While running i have discconected coil in cyl 2 and doesnt affect the engine rpms like the other coils do
Thanks in advance
George
An ignition misfire on one cylinder could cause all those codes, so don't assume that it must be a problem beyond #2.

Swapping coils like you did seems to eliminate them as the problem (of course, assuming the problem stayed on #2).

Swapping or replacing plugs as you did seems to eliminate them as the problem.

If you're concerned about the injector, you could use a "noid light" to see if the injector is getting the appropriate signal to fire, but that is not especially easy to get to (the connector to the injector).

I had a P1399 code (I don't think I had any others) and rough running earlier this year. I could not isolate it to one cylinder like you have, took lots of stuff apart, replaced fuel injectors, cleaned + re-torqued intake manifold gasket, and finally fixed it. I don't know for sure since I did so many things, but I think it was the intake manifold gasket and corresponding surfaces.
 

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Discussion Starter · #6 ·
thanks for the misfire codes and procedures Ill get started tomorrow thanks again:) I really wish it was a bad coil;(
make life easier:!
George
 

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It's a bad coil.
Don't bother swapping them.
Just unplug the electrical connector one at a time to each plug.
THE ONE THAT HAS NO CHANGE is the BAD one.
Good ones will all drop RPM when unplugged.
A bad one will show NO change when unplugged!

Go to Adv. Auto and get part E745.... $49.00

Replace it and your van will run fine.
10 minute job.
 

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Second retiredodyssey suggestion but I got two coils, one to replace the bad one and one to put in the glovebox as insurance that I won't have another one go bad... but just in case.
 

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It's a bad coil.
Don't bother swapping them.
Just unplug the electrical connector one at a time to each plug.
THE ONE THAT HAS NO CHANGE is the BAD one.
Good ones will all drop RPM when unplugged.
A bad one will show NO change when unplugged!

Go to Adv. Auto and get part E745.... $49.00

Replace it and your van will run fine.
10 minute job.

Go here for youtube fix

 
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