This was a great video by SMA
Engine Misfire, No Codes - Specific conditions
- Thread starter StevieC
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This is fairly normal for Ford trucks.
My F350 over it's 17 year life has gone through many coils. They'll die completely and it will not set a misfire code. It had a valve in one of the pistons and it still didn't have a check engine light.
My F350 over it's 17 year life has gone through many coils. They'll die completely and it will not set a misfire code. It had a valve in one of the pistons and it still didn't have a check engine light.
my AutoDoctor OBD reader supposedly has Mode6.
Shows no failures...but shows 0-4 misfires once in a while which all say is good to go.
Dealer checked, shows nothing.
symptoms show similar as video once in a while and changes from cylinder to cylinder. Not very significant and can't duplicate. Nowhere near as rough as the car in the video though.
Dealer said "needs tune up" which of course as I pointed out means only plugs...which I let them do (sad day for me, such an easy job).
No change.
Thinking it is transmission related. when under load, there is never an issue.
Light throttle or cruising on highway.
Shows no failures...but shows 0-4 misfires once in a while which all say is good to go.
Dealer checked, shows nothing.
symptoms show similar as video once in a while and changes from cylinder to cylinder. Not very significant and can't duplicate. Nowhere near as rough as the car in the video though.
Dealer said "needs tune up" which of course as I pointed out means only plugs...which I let them do (sad day for me, such an easy job).
No change.
Thinking it is transmission related. when under load, there is never an issue.
Light throttle or cruising on highway.
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I've seen coils breaking down slightly only under specific conditions. So it's enough to cause a bit of a stumble in the engine but not enough to trigger a misfire DTC. Some happen in gear at idle and others will happen when you step on it from a cruising speed or like above, in lock-up with light throttle going up a 1-2% grade.
This is when hooking up a scope and watching it as you recreate the conditions, can be helpful. Problem is most folks don't have access to a quality scope with enough resolution to see the problem so they either wait until it gets worse enough to set a DTC or they fire the parts canon and hope something fixes it.
Making it worse are lazy or unskilled mechanics that say, well if it's not setting a light there is nothing we can do, or they write it off as performing normally when the owner knows something is wrong.
I'm thankful to my dad who always asked "why" and wouldn't stop until things were perfect even when folks would think things are perfect to them. This taught me a lot about looking more closely at things. I would put SMA in that class. Eric O is excellent at looking past the obvious and getting to the bottom of something. Might take him a while to figure out but he never gives up.
This is when hooking up a scope and watching it as you recreate the conditions, can be helpful. Problem is most folks don't have access to a quality scope with enough resolution to see the problem so they either wait until it gets worse enough to set a DTC or they fire the parts canon and hope something fixes it.
Making it worse are lazy or unskilled mechanics that say, well if it's not setting a light there is nothing we can do, or they write it off as performing normally when the owner knows something is wrong.
I'm thankful to my dad who always asked "why" and wouldn't stop until things were perfect even when folks would think things are perfect to them. This taught me a lot about looking more closely at things. I would put SMA in that class. Eric O is excellent at looking past the obvious and getting to the bottom of something. Might take him a while to figure out but he never gives up.
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