Mystery Misfire

[HemiHog]

Hi all,

Basically I am out of options here. I drive an 09 1500 5.7L Hemi. For the past month now I have had a multi cylinder misfire code. I started off by pulling the spark plugs, in doing so I found 3/16 that looked like they were BBQ'ed. While replacing those I inspected the Coils/Boots, and injectors. I replaced the damaged coil and replaced all plugs. Unfortunately the code came back on. Anyone able to help a brother out?

 

[crash_eco]

What about the plugs?

 

[HemiHog]

Swapped out with NGK O.E.M's

 

[R/T_Fire]

This may sound funny but check your fuel pressure, you may have a failing pump that isn't delivering the right fuel, its enough to run but not perform 100%

Had a similar issue on my ZR2 turned out the fuel pressure was 5psi under spec. changed the pump and solved the problem, after I already replaced the whole ignition system

 

[HemiHog]

Pressure on par

 

[R/T_Fire]

The only other thing I can think of is a cam or crank position sensor. other than that I got nothing.

 

[HemiHog]

Check engine light is off now. Keeps going on and off

 

[Burla]

Same code every time? And there is no symptoms other then the CEL?

 

[HemiHog]

It was misfiring until I changed the plugs. Now it runs smooth, full power with CEL

 

[Burla]

So you fixed it but it might take a few days to clear. I would drive around in Tow/Haul mode and keep that MDS turned off and keep all of those cylinders firing good. Time to get a ported throttle body if it keeps up.

 

[HemiHog]

Ported throttle body? Lol

 

[HemiHog]

I was thinking to myself tonight about this issue. Could a faulty O2 sensor throw a misfire code?