P0300
#1
P0300
My truck has threw this code a couple of times the last couple of weeks. 210,000 miles 5.4 4x4. Cleaned throttle body, changed egr, iac as maintenance. Code came up after this. Should I look into swapping coil packs as maintenance? $320 for 8 motorcraft at dieselfiltersonline. Fuel pressure seems good. Plugs were changed 40,000 ago. It does idle a little rough, but runs strong and smooth on road.
#2
Have you looked up what the code is telling you?
It will tell you 'random' missifire.
Do not begin changing coils for a 'random' missfire or look at fuel hardware. To that extent, it could be water in the gas that would be random in nature through the injectors.
First place to check is the plug seating on the crank sensor.
Use the code to tell you where to begin instead of guessing.
Random means the PCM cannot tell any 'specific' cylinder is the cause or it would tell you which one it is by a code 301 through 308.
A random indication suggest a fault common to the whole system operation.
The crank sensor, plug or harness is first in line to check out.
.
If the missfire comes under a specific set of driving conditions such as in OD under light throttle, then it could well be one coil but you have not indicated that was the case.
Sorry to get on your back but you need to think about this a bit more so you can trust useing codes and their discriptions to start troubleshooting with.
The system is smarter than your guessing would be and a lot less expensive.
One of my reasons for my being here is to get owners and readers to understand what they own and how much more they have to understand about it for self help.
Good luck.
It will tell you 'random' missifire.
Do not begin changing coils for a 'random' missfire or look at fuel hardware. To that extent, it could be water in the gas that would be random in nature through the injectors.
First place to check is the plug seating on the crank sensor.
Use the code to tell you where to begin instead of guessing.
Random means the PCM cannot tell any 'specific' cylinder is the cause or it would tell you which one it is by a code 301 through 308.
A random indication suggest a fault common to the whole system operation.
The crank sensor, plug or harness is first in line to check out.
.
If the missfire comes under a specific set of driving conditions such as in OD under light throttle, then it could well be one coil but you have not indicated that was the case.
Sorry to get on your back but you need to think about this a bit more so you can trust useing codes and their discriptions to start troubleshooting with.
The system is smarter than your guessing would be and a lot less expensive.
One of my reasons for my being here is to get owners and readers to understand what they own and how much more they have to understand about it for self help.
Good luck.
#5
Have you looked up what the code is telling you?
It will tell you 'random' missifire.
Do not begin changing coils for a 'random' missfire or look at fuel hardware. To that extent, it could be water in the gas that would be random in nature through the injectors.
First place to check is the plug seating on the crank sensor.
Use the code to tell you where to begin instead of guessing.
Random means the PCM cannot tell any 'specific' cylinder is the cause or it would tell you which one it is by a code 301 through 308.
A random indication suggest a fault common to the whole system operation.
The crank sensor, plug or harness is first in line to check out.
.
If the missfire comes under a specific set of driving conditions such as in OD under light throttle, then it could well be one coil but you have not indicated that was the case.
Sorry to get on your back but you need to think about this a bit more so you can trust useing codes and their discriptions to start troubleshooting with.
The system is smarter than your guessing would be and a lot less expensive.
One of my reasons for my being here is to get owners and readers to understand what they own and how much more they have to understand about it for self help.
Good luck.
It will tell you 'random' missifire.
Do not begin changing coils for a 'random' missfire or look at fuel hardware. To that extent, it could be water in the gas that would be random in nature through the injectors.
First place to check is the plug seating on the crank sensor.
Use the code to tell you where to begin instead of guessing.
Random means the PCM cannot tell any 'specific' cylinder is the cause or it would tell you which one it is by a code 301 through 308.
A random indication suggest a fault common to the whole system operation.
The crank sensor, plug or harness is first in line to check out.
.
If the missfire comes under a specific set of driving conditions such as in OD under light throttle, then it could well be one coil but you have not indicated that was the case.
Sorry to get on your back but you need to think about this a bit more so you can trust useing codes and their discriptions to start troubleshooting with.
The system is smarter than your guessing would be and a lot less expensive.
One of my reasons for my being here is to get owners and readers to understand what they own and how much more they have to understand about it for self help.
Good luck.
#6
The code by it's nature and discription is not a 'hard' fault so may not cause the CEL to light.
Some logic on why the code sets.
With the rough idle tendency you see, the crank sensor measures the crank rotation time for every cylinder everytime cylinder ignition occurrs.
So the rough idle is being detected as a random missfires due to the cause of the roughness affecting 'all' cylinders in a random fashion.
To check if the EGR may be being held open a small amount due to a faulty EVR, remove the EGR hose. If the idle settles you have an issue with the EVR sticking partly open.
Otherwise water in the fuel could be a cause of random missfire, intermittant harness plugs etc. Anything that would upset continued operation on either a momentary mechanical or temperature sensitive nature.
Fuel system issues usually do not cause a random missfire and still allow the motor to run up to road speeds without an issue.
Just takes looking from these points of view until you get it.
It may be of help to look a the live data with a scanner, beyond just the codes.
Goord luck.
Some logic on why the code sets.
With the rough idle tendency you see, the crank sensor measures the crank rotation time for every cylinder everytime cylinder ignition occurrs.
So the rough idle is being detected as a random missfires due to the cause of the roughness affecting 'all' cylinders in a random fashion.
To check if the EGR may be being held open a small amount due to a faulty EVR, remove the EGR hose. If the idle settles you have an issue with the EVR sticking partly open.
Otherwise water in the fuel could be a cause of random missfire, intermittant harness plugs etc. Anything that would upset continued operation on either a momentary mechanical or temperature sensitive nature.
Fuel system issues usually do not cause a random missfire and still allow the motor to run up to road speeds without an issue.
Just takes looking from these points of view until you get it.
It may be of help to look a the live data with a scanner, beyond just the codes.
Goord luck.
#7
The code by it's nature and discription is not a 'hard' fault so may not cause the CEL to light.
Some logic on why the code sets.
With the rough idle tendency you see, the crank sensor measures the crank rotation time for every cylinder everytime cylinder ignition occurrs.
So the rough idle is being detected as a random missfires due to the cause of the roughness affecting 'all' cylinders in a random fashion.
To check if the EGR may be being held open a small amount due to a faulty EVR, remove the EGR hose. If the idle settles you have an issue with the EVR sticking partly open.
Otherwise water in the fuel could be a cause of random missfire, intermittant harness plugs etc. Anything that would upset continued operation on either a momentary mechanical or temperature sensitive nature.
Fuel system issues usually do not cause a random missfire and still allow the motor to run up to road speeds without an issue.
Just takes looking from these points of view until you get it.
It may be of help to look a the live data with a scanner, beyond just the codes.
Goord luck.
Some logic on why the code sets.
With the rough idle tendency you see, the crank sensor measures the crank rotation time for every cylinder everytime cylinder ignition occurrs.
So the rough idle is being detected as a random missfires due to the cause of the roughness affecting 'all' cylinders in a random fashion.
To check if the EGR may be being held open a small amount due to a faulty EVR, remove the EGR hose. If the idle settles you have an issue with the EVR sticking partly open.
Otherwise water in the fuel could be a cause of random missfire, intermittant harness plugs etc. Anything that would upset continued operation on either a momentary mechanical or temperature sensitive nature.
Fuel system issues usually do not cause a random missfire and still allow the motor to run up to road speeds without an issue.
Just takes looking from these points of view until you get it.
It may be of help to look a the live data with a scanner, beyond just the codes.
Goord luck.
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#8
#10
Connection is tight. I pulled it to inspect, and I noticed the interior of the plug and the prongs on the sensor are slightly oily with motor oil. Is this normal?
#11
#12
A couple more questions, would the coating of motor oil on the prongs cause a bad connection? And is the grease you're referring to the same thing as dielectric grease?
#13
Motor oil combined with dirt etc may cause poor contact.
I'm not sure what difference there is between dielectric grease and the grease used for connectors.
The connector grease is usually pure white as opposed to semi clear dielectric grease.
There is a type called NO-OXIDE-A but don't think you could ever locate any on the consumer market.
It's used in industry for battery buss bar connections in high current power systems and sticks like permant and totally water resistant and very sticky.
I'm not sure what difference there is between dielectric grease and the grease used for connectors.
The connector grease is usually pure white as opposed to semi clear dielectric grease.
There is a type called NO-OXIDE-A but don't think you could ever locate any on the consumer market.
It's used in industry for battery buss bar connections in high current power systems and sticks like permant and totally water resistant and very sticky.
#14
Motor oil combined with dirt etc may cause poor contact.
I'm not sure what difference there is between dielectric grease and the grease used for connectors.
The connector grease is usually pure white as opposed to semi clear dielectric grease.
There is a type called NO-OXIDE-A but don't think you could ever locate any on the consumer market.
It's used in industry for battery buss bar connections in high current power systems and sticks like permant and totally water resistant and very sticky.
I'm not sure what difference there is between dielectric grease and the grease used for connectors.
The connector grease is usually pure white as opposed to semi clear dielectric grease.
There is a type called NO-OXIDE-A but don't think you could ever locate any on the consumer market.
It's used in industry for battery buss bar connections in high current power systems and sticks like permant and totally water resistant and very sticky.
Also, my tranny seems to be downshifting more normally since I've put more miles on the reset computer. After I got the p1740 code and I reset it, it seemed to have corrected itself.
#15
It's been quite a learning curve for you.
Hope the TCC code does not come back to haunt.
Once there is a detected issue it usually does not fix it's self permantly.
The PCM constantly monitors for shorts, opens and slow or stuck operations by looking at the operating current 'signiture' during operation by comparing to an information table in software, but good luck to you..
Hope the TCC code does not come back to haunt.
Once there is a detected issue it usually does not fix it's self permantly.
The PCM constantly monitors for shorts, opens and slow or stuck operations by looking at the operating current 'signiture' during operation by comparing to an information table in software, but good luck to you..