Engine Missfire Codes P0300, p0302

[SD_GT]

Rich, any update? My car just started doing this after my clutch install.

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[Silver550]

Rich, any update? My car just started doing this after my clutch install.

They took the valve cover off to inspect the motor and nothing, I spoke with the Ford tech yesterday and they told me that they are going to replace the o2 sensors and give that a try. I am not sure how 02 sensors would cause a check engine/misfire light. At this point I don't care what they try as long as they are trying to figure it out.

 

[astolt12]

They took the valve cover off to inspect the motor and nothing, I spoke with the Ford tech yesterday and they told me that they are going to replace the o2 sensors and give that a try. I am not sure how 02 sensors would cause a check engine/misfire light. At this point I don't care what they try as long as they are trying to figure it out.

If the car isnt receiving the right AF mixture it can and will. I had a tuned '11 that blew an o2 sensor and didnt throw a CEL. Randomly started misfiring.

Eventually replaced the left hand side bank 1 sensor. Fixed it.

 

[Silver550]

If the car isnt receiving the right AF mixture it can and will. I had a tuned '11 that blew an o2 sensor and didnt throw a CEL. Randomly started misfiring.

Eventually replaced the left hand side bank 1 sensor. Fixed it.

Ok, good to hear that something this simple could cause this issue.

 

[cbrtrx]

Rich, any update? My car just started doing this after my clutch install.

You need to do a crank relearn most likely.

 

[Silver5.0]

If the car isnt receiving the right AF mixture it can and will. I had a tuned '11 that blew an o2 sensor and didnt throw a CEL. Randomly started misfiring.

Eventually replaced the left hand side bank 1 sensor. Fixed it.

This is interesting. Was your car not getting the right AF mixture due to the tune? My car is back in the shop for intermittent CEL... again.

 

[astolt12]

This is interesting. Was your car not getting the right AF mixture due to the tune? My car is back in the shop for intermittent CEL... again.

Not sure. I didn't have anything to measure AF at the time; but promptly bought some AF pillar gauges and never had the problem again after some re routing.

Im not sure how the S550s are but the S197 if an HO2S went out then it would run the car off the other HO2S. This is OK if you're not goosing it, but when your car is built to have two O2 sensors (one for left, one for right) at WOT you can run into mis-fire/detonation issues.

What one side of the engine is doing isnt necessarily what the other side should be doing.

 

[cdmustang2016]

It backfires under light acceleration.

I have the same issues. Car has been in service more time than I have had it. Last time I saw it was July 8th. Ford has been zero help. The blamed Roush supercharger, which was installed by dealer by the book, supposedly not voiding warranty. But when time came Ford told me not their problem. And this is from Ford corporate. Shameful.

I did pay for the Roush additional warranty and the shipped car to Michigan to problem solve. But I am not hopeful. I feel it is a baseline Ford defect. Ford customer service and Ford Performance tried blaming dealer, then Roush etc. What is the point of going to FORD if they don't even honor their warranty.

I am seeing more people having the same issue now. I had the issue from the day I took delivery of my car this May.

 

[Silver550]

update, so the dealership replaced an o2 sensor and it did not fix the issue. I will finally get a loaner car on monday. I have been fighting for a loaner car since day one and It has been a while and I am finally going to be getting one. I would rather have my own car back. Ford needs to look into this issue, it seems that its starting to become a common issue.

 

[cdmustang2016]

update, so the dealership replaced an o2 sensor and it did not fix the issue. I will finally get a loaner car on monday. I have been fighting for a loaner car since day one and It has been a while and I am finally going to be getting one. I would rather have my own car back. Ford needs to look into this issue, it seems that its starting to become a common issue.

Sorry to hear. My car went through 2 dealers. With assistance from Ford Performance and no one had a clue how to resolve. Now it's in Roush's lap but I lost hope. Now been at Roush for over a week. They confirmed there is misfiring but no resolution yet. It's a shame Ford does can't figure it out. I am sure we aren't the only ones.

 

[Silver5.0]

I was told last Friday they are going to replace the head on my car. I don't know how they came to that conclusion but we will see if this fixes it. I get it back tomorrow.

 

[astolt12]

I was told last Friday they are going to replace the head on my car. I don't know how they came to that conclusion but we will see if this fixes it. I get it back tomorrow.

I would push for a whole new block...instead of a new top-end.

 

[Silver550]

I was told last Friday they are going to replace the head on my car. I don't know how they came to that conclusion but we will see if this fixes it. I get it back tomorrow.

Dude, let us know how it came out. I was approved for a car rental finally. It's a joke they set me up with a Transit, ha ha a little mini van looking suv/van. its hideous. But it really helps having a second car again.

 

[Silver5.0]

Dude, let us know how it came out. I was approved for a car rental finally. It's a joke they set me up with a Transit, ha ha a little mini van looking suv/van. its hideous. But it really helps having a second car again.

I certainly will. Ford was nice enough to set me up with a rental too... a fusion. I immediately missed the power of my mustang.

 

[cdmustang2016]

I certainly will. Ford was nice enough to set me up with a rental too... a fusion. I immediately missed the power of my mustang.

Def keep us informed. I'm still waiting to hear from Roush

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