P0308 and P0304 mystery misfire
Today, 01:33 PM
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P0308 and P0304 mystery misfire
Hey there,
hey everyone i’m coming on here to ask for some help with my 05 mustang gt automatic tranny with 137xxx miles, vehicle has a cold air intake that has been there since i bought it and from what i know has been on it for a while and a cat back with a muffler delete, i’m unsure if it’s been tuned or flashed due to little info from the previous owner. i think it’s worth noting i am a technician but i am completely stumped right now.
I am having an issue with a misfire on cylinder 8 and 4, some background is that i bought the car about 3-4 months ago and had to replace the alternator relatively early on due to a camshaft position code, my alternator was undercharging and setting a camshaft position code, i replaced the alternator and verified it is charging correctly now under load and full field. cleared codes and reset KAM code has never came back. a couple weeks later it started misfiring and random misfiring so i pulled the plugs and found them to be worn down but i swapped coils and plugs before making a decision and the misfire followed so i changed out all my coil packs and plugs with motorcraft parts (alternator is motorcraft as well.) same thing i cleared codes reset KAM, car ran great afterwards i had noticed a stutter from a stop when i bought it and that cleared up as well.
Recently about 2-3k miles after i was driving the car and got a CEL, checked codes it was running lean i inspected my intake system and noticed my intake boot was loose so i tightened that and cleared codes, about 3 days after i noticed the stutter come back again very slightly from stops, and then i started getting backfire from the exhaust and check engine light flashing, i pulled over and shut it off and was gonna go get my scanner but when i restarted the car check engine light was off and the car was running fine and no codes were present, so i checked memory codes and it said cylinder 8 misfire. i started with the basics again and swapped coils from 7 to 8 and injectors as well from 7 to 8, cleared codes and drove the vehicle around. a couple days later it seemed to have cleared up and my scanner Wasn’t showing any misfires other than 1 every drive cycle on 8.
Well i kept driving it to try and get it to act up again and of course the day i didn’t have my scanner hooked up i was driving it pretty hard and came to a stop and it started misfiring pretty hard, so i pulled over, shut it off and was gonna call a buddy to come bring me my scanner and maybe tow it back to my house. i turned it on again, misfire was gone and it was running fine again. i got to my trade school and scanned codes with one of their scanners and it said i was misfiring on number 4 now and i also had a misfire on start up detected. i smoked my intake to see if i could find any leaks but i didn’t see any, however i do smell a little bit of what seems like gas around the drivers side intake manifold so now im suspecting a intake possibly or something to do with injectors or maybe even a fuel filter being clogged, my fuel pressure seems to be good on freeze frame data and scanner data, desired and actual match under all conditions. so im kinda lost now, the stutter is currently still there intermittently coming from stops and i just cleared codes to try and view data regarding misfires per drive cycle.3
I’m kinda looking to see if anyone has had anything similar happen, what are the chances oem plugs and coils are faulty? or what are the chances i have a small leak on my intake manifold or the runners are going out? should i try a fuel filter? or is it possibly just clogged injectors even thought it didn’t really follow? thank you in advanced and sorry if this is long and hard to read this is my first time posting and if i need to change anything or if yall need more info let me know.
hey everyone i’m coming on here to ask for some help with my 05 mustang gt automatic tranny with 137xxx miles, vehicle has a cold air intake that has been there since i bought it and from what i know has been on it for a while and a cat back with a muffler delete, i’m unsure if it’s been tuned or flashed due to little info from the previous owner. i think it’s worth noting i am a technician but i am completely stumped right now.
I am having an issue with a misfire on cylinder 8 and 4, some background is that i bought the car about 3-4 months ago and had to replace the alternator relatively early on due to a camshaft position code, my alternator was undercharging and setting a camshaft position code, i replaced the alternator and verified it is charging correctly now under load and full field. cleared codes and reset KAM code has never came back. a couple weeks later it started misfiring and random misfiring so i pulled the plugs and found them to be worn down but i swapped coils and plugs before making a decision and the misfire followed so i changed out all my coil packs and plugs with motorcraft parts (alternator is motorcraft as well.) same thing i cleared codes reset KAM, car ran great afterwards i had noticed a stutter from a stop when i bought it and that cleared up as well.
Recently about 2-3k miles after i was driving the car and got a CEL, checked codes it was running lean i inspected my intake system and noticed my intake boot was loose so i tightened that and cleared codes, about 3 days after i noticed the stutter come back again very slightly from stops, and then i started getting backfire from the exhaust and check engine light flashing, i pulled over and shut it off and was gonna go get my scanner but when i restarted the car check engine light was off and the car was running fine and no codes were present, so i checked memory codes and it said cylinder 8 misfire. i started with the basics again and swapped coils from 7 to 8 and injectors as well from 7 to 8, cleared codes and drove the vehicle around. a couple days later it seemed to have cleared up and my scanner Wasn’t showing any misfires other than 1 every drive cycle on 8.
Well i kept driving it to try and get it to act up again and of course the day i didn’t have my scanner hooked up i was driving it pretty hard and came to a stop and it started misfiring pretty hard, so i pulled over, shut it off and was gonna call a buddy to come bring me my scanner and maybe tow it back to my house. i turned it on again, misfire was gone and it was running fine again. i got to my trade school and scanned codes with one of their scanners and it said i was misfiring on number 4 now and i also had a misfire on start up detected. i smoked my intake to see if i could find any leaks but i didn’t see any, however i do smell a little bit of what seems like gas around the drivers side intake manifold so now im suspecting a intake possibly or something to do with injectors or maybe even a fuel filter being clogged, my fuel pressure seems to be good on freeze frame data and scanner data, desired and actual match under all conditions. so im kinda lost now, the stutter is currently still there intermittently coming from stops and i just cleared codes to try and view data regarding misfires per drive cycle.3
I’m kinda looking to see if anyone has had anything similar happen, what are the chances oem plugs and coils are faulty? or what are the chances i have a small leak on my intake manifold or the runners are going out? should i try a fuel filter? or is it possibly just clogged injectors even thought it didn’t really follow? thank you in advanced and sorry if this is long and hard to read this is my first time posting and if i need to change anything or if yall need more info let me know.
Today, 01:57 PM
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Welcome,
Thanks For All The Background Info To Help With Your Issue. How About We Identify Your Cai and See if it is One That Needs a Tune. Also Does it Use a Wet K&N Filter Which if Over oiled Can Cause Issues. Any ID Marks and a Picture of CAI Would Be Helpful. An Oily MAF Can Cause Some Odd Issues as Well! Also If MAF Does Not Seal Well to Filter Housing it Will Wreak Havoc! Been There With My Gt-500! Barely Ran Due To Improper Sealing of MAF.
Some Nice Pics of The Underhood Area May Provide Clues as To Other Possible Issues!
The Fuel Filter is a No Brainer Install For Peace of Mind!
The Dtc Section in Here Will Give a Troubleshooting Process By Codes as Well.
Link For Reference. I Pulled The Section For Your Listed Trouble Codes & Also Added Misfire Detection Troubleshooting From Shop Manual!
https://themustangsource.com/forums/...e-info-550470/
Kc
P030x - Misfire Detection Monitor
Description: The misfire detection monitor is designed to monitor engine misfire and identify the specific cylinder in which the misfire has occurred. Misfire is defined as
lack of combustion in a cylinder due to absence of spark, poor fuel metering, poor compression, or any other cause.
NOTE: x represents cylinder number 1 through 9.
Possible
Causes:
Ignition system
Fuel injectors
Running out of fuel
EVAP canister purge valve
Fuel pressure
Evaporative emission system
EGR system
Base engine
Diagnostic
Aids:
The malfunction indicator lamp (MIL) blinks once per second when a misfire severe enough to cause catalyst damage is detected. If the MIL is on steady
state due to a misfire, this indicates the threshold for emissions was exceeded and caused the vehicle to fail an inspection and maintenance tailpipe test.
Application Key On Engine Off Key On Engine Running Continuous Memory
All — — GO t HD 1
See Misfire PDF.
Thanks For All The Background Info To Help With Your Issue. How About We Identify Your Cai and See if it is One That Needs a Tune. Also Does it Use a Wet K&N Filter Which if Over oiled Can Cause Issues. Any ID Marks and a Picture of CAI Would Be Helpful. An Oily MAF Can Cause Some Odd Issues as Well! Also If MAF Does Not Seal Well to Filter Housing it Will Wreak Havoc! Been There With My Gt-500! Barely Ran Due To Improper Sealing of MAF.
Some Nice Pics of The Underhood Area May Provide Clues as To Other Possible Issues!
The Fuel Filter is a No Brainer Install For Peace of Mind!
The Dtc Section in Here Will Give a Troubleshooting Process By Codes as Well.
Link For Reference. I Pulled The Section For Your Listed Trouble Codes & Also Added Misfire Detection Troubleshooting From Shop Manual!
https://themustangsource.com/forums/...e-info-550470/
Kc
P030x - Misfire Detection Monitor
Description: The misfire detection monitor is designed to monitor engine misfire and identify the specific cylinder in which the misfire has occurred. Misfire is defined as
lack of combustion in a cylinder due to absence of spark, poor fuel metering, poor compression, or any other cause.
NOTE: x represents cylinder number 1 through 9.
Possible
Causes:
Ignition system
Fuel injectors
Running out of fuel
EVAP canister purge valve
Fuel pressure
Evaporative emission system
EGR system
Base engine
Diagnostic
Aids:
The malfunction indicator lamp (MIL) blinks once per second when a misfire severe enough to cause catalyst damage is detected. If the MIL is on steady
state due to a misfire, this indicates the threshold for emissions was exceeded and caused the vehicle to fail an inspection and maintenance tailpipe test.
Application Key On Engine Off Key On Engine Running Continuous Memory
All — — GO t HD 1
See Misfire PDF.
Today, 02:29 PM
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Looks Like it and Says Nothing About a Tune! I Would Still Check & Clean MAF as a Start!
Kc
Kc
Today, 02:34 PM
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thank you, i have cleaned it before but just removed it and cleaned it off with some non chlorinated brake clean, i assume it’s sealing correctly due to no smoke coming out around there when i smoke tested it. i will reset kam and clear codes after it dries off and see if it makes a difference. what should i do from here? should i also just replace a fuel filter ? any recommend brands?
Today, 02:38 PM
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thank you, i have cleaned it before but just removed it and cleaned it off with some non chlorinated brake clean, i assume it’s sealing correctly due to no smoke coming out around there when i smoke tested it. i will reset kam and clear codes after it dries off and see if it makes a difference. what should i do from here? should i also just replace a fuel filter ? any recommend brands?
Always Use a MAF CLEANER for MAF's and Always Use Throttle Body Cleaners on Throttle Bodies Vs Carb Cleaners! The Smart Thing To Do! Keep Brake Clean on Brakes! Maf's Are Quite Sensitive to Certain Chemicals & Films Left On Them.
These Are Good!
A Good Throttle Body Clean is Always Helpful to Keep Er Running Good!
I Would Go Through The Diag in Post 2 Starting at HD1 in The Misfire Pdf and Follow The Trail as FORD Lays it Out Along With Other Things Discussed. That's What I Have & Perhaps Some Other Members Have Had a Similar Issue & Will Chime In But For Now You Have a Bit of a New Path To Follow!
KC
Today, 03:04 PM
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Since The Car is New To You I Would Advise You Check For Water Intrusion Issues as Laid Out in this Thread & TSB! It's a Common Issue and Can Cause a Bunch of Different Issues Down The Road!
If You Have Cruddy Connections on SJB a Cleaner Like This Will Work Well!
https://themustangsource.com/forums/...26-7-a-550617/
If You Have Cruddy Connections on SJB a Cleaner Like This Will Work Well!
https://themustangsource.com/forums/...26-7-a-550617/
Today, 03:07 PM
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okay, i just ordered a motorcraft fuel filter should be here in an hour, recleaned the sensor with maf cleaner. i appreciate all the help and i do have access to all data and mitchell, so i do have access to all of fords misfire PPT’S, and TSBS. thank you for all your help so far i will keep you updated on it after i put the fuel filter in and reset KAM. i suspect this filter will help it because i doubt its ever been changed.
Today, 03:09 PM
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You Are Welcome & We Look Forward To Solving Another S-197 Mystery!
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Kc
Today, 03:11 PM
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also worth noting, i live in colorado where it rains a good amount however i have no had any water intrusion issues so far. everything interior is dry from what i can tell. i dunno if mine got a TSB done before but no water is present around SJB or on floorboard.
Today, 03:14 PM
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Need To Pop The Cowl & Check Drains Below Cabin Filter. Could Be Full of Leaves Etc. Probably Needs Filter Anyway! Many Times SJB gets Wet Without Floor Showing Signs! Having To Replace Sjb & Program Can get Spendy So Good To Be Sure No Issues! Any Green Looking Crud on SJb Plug Connections are Just Problems That Will Surface as Time Goes On. A Look inside The Cowl Will Tell The Tale if it's Been Full of Water in The Past. Some in The Past Would Have Issues Surface After Going Through a Car Wash As it Overloaded The Area Due To Plugged Drains. A Quick Look at Filter Area Should Indicate if All is Well or Questionalble.
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