Hello,

I am having problems with my mustang misfiring at random times. At first a few months ago, I had replaced the motor and it was fine for a while (7,000 miles) until it started misfiring. Read the codes and swapped coils/replaced them as needed as well with the spark plugs. I’ve tried multiple brands like Duralast and NGK coils, a fresh set of coils AND spark plugs, and the misfire randomly comes back and a coil will go bad, so I am lost for words. The traditional “swap coil pack to another cylinder” doesn’t work because the coil goes bad, but the problem is I can’t figure out why it keeps going bad randomly. The car idles fine and only starts to misfire when I get on it, full throttle.

 

Welcome,

Have You Pulled Any Codes?

Need To Check with a Code Reader That Can Check Both B& P Codes. Should Be Some Sort of Clue There!

When You Say Replaced The Motor Please Specify.

A Reman or a Used and if Used Was it Out Of Same Year Mustang?? What Was Wrong With Original Engine??

KC

 

i replaced motor with a brand new one from ford with same year after it overheated sadly. no other codes besides misfires

 

If You Will Provide actual Code Numbers I Will Pull Ford Shop Manual Diag Chart Process for Them. Also Sometimes There is a TSB Related To A Particular Code. PM Me a Vin and I Can Narrow Down The TSB Section to Be Sure it Applies To Your Vehicle.

Again Does Your Reader Pull B- Codes As Well??

If Not We could Be Missing another Avenue To Investigate.

Kc

 

You Did Reset The Misfire Monitor When Engine Was Replaced??

KC

 

The codes are basic misfires that keep coming back, P0301-P0304. All cylinders would have a moment where they would misfire from 1-4 randomly at any given time when I would hard accelerate, and then a coil would go bad. Don’t know what to do next, I’m guessing the PCM (main computer board monitor) but I don’t have any other symptoms of a bad PCM besides this randomly misfiring going on. Maybe the alternator is over charging stuff? I have no idea. I had no idea I had to reset the misfire monitor so I will do that now. I haven’t had the codes ever since replacing the last bad coil but pulled a full system report so I have some data I can give you if you need it.

 

this is everything the code reader gave me when i ran it today not to long ago.

 

I Double Checked To Be Sure The Ecoboost Automatic Needs The Misfire Monitor Correction and it Does.

Maybe Your Issue!

Give it a Shot!

See Last Page of Engine Installation Instructions I Provided in Pdf. For Reference.

Also Reference Info Related To Trouble Codes as an FYI.

A Good Start Anyway!


KC

 

Here is The FORD DTC Section For Your Codes!

PCM P0300 Random/Multiple Cylinder Misfire Detected Description

• This DTC sets when the misfire detection monitor detects an engine misfire in multiple cylinders or the PCM cannot identify which cylinder is misfiring.

Possible Causes

• Damaged camshaft position (CMP) sensor
• Low fuel (less than 1/8 tank)
• Stuck open exhaust gas recirculation (EGR) valve
• Restricted EGR passages
• Misfire monitor neutral profile correction has not been relearned since the last mechanical repair

Diagnostic Aids

• One or more EGR passages may be restricted.

GO to Pinpoint Test HD PCM P0301 Cylinder 1 Misfire Detected Description

• This DTC sets when the misfire detection monitor detects an engine misfire in cylinder 1.

Possible Causes

• Ignition system
• Fuel injector 1
• Running out of fuel
• EVAP purge valve
• Fuel pressure
• Evaporative emission system
• Exhaust gas recirculation (EGR) system
• Base engine
• Misfire monitor neutral profile correction has not been relearned since the last mechanical repair

Diagnostic Aids

• Misfire is defined as lack of combustion in a cylinder due to absence of spark, incorrect fuel metering, low compression, or any other cause.
• 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.

GO to Pinpoint Test HD PCM P0302 Cylinder 2 Misfire Detected Description

• This DTC sets when the misfire detection monitor detects an engine misfire in cylinder 2.

Possible Causes

• Ignition system
• Fuel injector 2
• Running out of fuel
• EVAP purge valve
• Fuel pressure
• Evaporative emission system
• Exhaust gas recirculation (EGR) system
• Base engine
• Misfire monitor neutral profile correction has not been relearned since the last mechanical repair

Diagnostic Aids

• Misfire is defined as lack of combustion in a cylinder due to absence of spark, incorrect fuel metering, low compression, or any other cause.
• 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.

GO to Pinpoint Test HD PCM P0303 Cylinder 3 Misfire Detected Description

• This DTC sets when the misfire detection monitor detects an engine misfire in cylinder 3.

Possible Causes

• Ignition system
• Fuel injector 3
• Running out of fuel
• EVAP purge valve
• Fuel pressure
• Evaporative emission system
• Exhaust gas recirculation (EGR) system
• Base engine
• Misfire monitor neutral profile correction has not been relearned since the last mechanical repair

Diagnostic Aids

• Misfire is defined as lack of combustion in a cylinder due to absence of spark, incorrect fuel metering, low compression, or any other cause.
• 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.

GO to Pinpoint Test HD PCM P0304 Cylinder 4 Misfire Detected Description

• This DTC sets when the misfire detection monitor detects an engine misfire in cylinder 4.

Possible Causes

• Ignition system
• Fuel injector 4
• Running out of fuel
• EVAP purge valve
• Fuel pressure
• Evaporative emission system
• Exhaust gas recirculation (EGR) system
• Base engine
• Misfire monitor neutral profile correction has not been relearned since the last mechanical repair

Diagnostic Aids

• Misfire is defined as lack of combustion in a cylinder due to absence of spark, incorrect fuel metering, low compression, or any other cause.
• 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

 

what is the torque spec for a 2015 mustang eco boost premium intake manifold ?

 

Here is Manifold R&R With Specs!

KC

 

what about torque specs for the fuel rails and fuel injectors ? also i appreciate u so much like you actually have no idea

 

Your Welcome!

Let Me Know if You Need Any Other Shop Manual Info!

Be Careful With The Fuel System it is Under very High Pressure!

As You Will Find Some of The Pieces Related May Be One Use Bolts and Some Components.

See PDF For Specs!

KC