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Discussion Starter · #1 ·
Hello Everyone,
I have a 2006 5.7L Commander that one morning started up rough and smoke started spewing out of the tailpipe a few moments later the check engine light went on Code P0307 and this started a week long drinking binge with me mostly staring out the window at the car and angrily drinking whiskey. After my hangover had cleared up I decided to start checking forums to see what I was up against, I basically had myself convinced that the issue was that the heads needed to be replaced. I am no mechanic and wasn't sure replacing them was something I could do myself. So before I went for laying down $3500 to have someone do it for me I decided it best to start checking cheaper causes just to make sure I needed to,
Checked spark plugs (all good but replaced the two in number 7 anyways) still misfiring

Checked coil packs electrical wiring (all good)

Replaced the oil (not sure why this would help but I was told to do it) still misfiring

Finally on a whim and a prayer I checked the PCV valve BINGO! the valve was in backwards and had been that way for a few months this apparently caused build up on the valves and back pressure to keep them from seating properly.
I flipped that sucker around and immediately the misfire stopped.

I still have smoke coming out of the tail pipe but far less and it seems to get less every day, I have put fuel injection cleaner in the gas (STP Concentrated) and I have a can of CRC cleaner to spray directly in the intake and I am hoping this will clear it up.

Does anyone know of any other injection cleaners I should use to try and get out the carbon build up?

I tell the whole story on the chance that someone else might be having the same problem and may have been stupid enough to install the PCV valve backwards (like myself)
 

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Pcv valve

The PCV Valve is short for Positive Crankcase ventilation, so it is my thought that a fuel injection cleaner may clean the injector and some of the combustion chamber but may not clean the back side of the valve or the valve seat. Possibly now that you have it in correctly just a good long trip on the highway may break the carbon off of the back of the valves, as the fuel only enters through the intake but you still want the exhaust to seat as well. keep an eye on it but city driving may not be enough you need to get the motor up to temp and let it break up as much as you can.


Swanny
 

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2006 Commander Limited, 5.7 Hemi QD2
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1,306 Posts
You could add some Sea Foam to the gas tank, have read good things about it.
Hey It's a hemi, self cleaning - do some fast/hard starts and wind it out for a quarter mile or so, I do it every so often just for that reason. Just do not do a short burst, all that carbon may get loosened up and foul the plugs - run it for about 30 seconds or more at high rpm. I had a 57 Chevy V8, did a short run like that and fouled all 8 plugs, had to take several of them out and clean them to get it to start.
 
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