Sponsored

Misfire codes (P0308, P0306, P0300) on a stock gen2 coyote with 60k miles

Shifting_Gears

Well-Known Member
Joined
Sep 13, 2018
Threads
88
Messages
2,025
Reaction score
1,686
Location
South Florida
Vehicle(s)
2016 Mustang GT
I had the same behavior across #6 and #8. No matter what coils I had on the plug the same ones kept throwing codes.

When I pulled the intake and found those broken flappers thats when I knew. It was always misfiring on just one side. Here's the post with the video in it:

https://www.mustang6g.com/forums/th...ote-with-60k-miles.177596/page-2#post-3607646

So you may be faced with the same choice I had. i decided to leap and get the Power Pack 3 upgrade and move to a GT350 intake. At the very least have an 18+ intake on hand before you pull your old one. If you end up installing the 18+ I believe you have to add a tune, but you'd use the Pro-Cal tool with the GT350 intake anyway. Either way you're most likely saying bye bye to the 15-17 intake. Mine is still broken, but in the box. Not sure if it's worth fixing, but I appreciate the fact that it can be.
Yup.. same story with mine. Actuator rod snapped. If I always drove at WOT, it wouldn't have mattered... but the car ran like hot dog sheet at partial throttle.
Sponsored

 

TexasRebel

Gearshifter
Joined
Mar 19, 2016
Threads
27
Messages
2,500
Reaction score
836
Location
between the mustard and the mayo
Vehicle(s)
2016 YZ GTPP - PP2
At first I thought it was the actuator rod, especially when I got the P0300 code, but after I cleared that, it's been all P0301 codes. I'm going to order injectors and change all 8 because that's a cheaper repair that probably needs to be done anyway.

I'd be quicker to think it's the broken actuator rod if I saw a P0302, P0303, or P0304 sometime.

Also, I need to go switch the #1 and #2 coils. I swapped #5 and #6 earlier. I knew Ford numbers down the banks instead of the crankshaft, but I had the wrong side. I don't care what anyone thinks, cylinders should be numbered front to back.
 

ypena02

Well-Known Member
Joined
Nov 14, 2015
Threads
27
Messages
787
Reaction score
200
Location
Massachusetts
Vehicle(s)
2017 Mustang GT

TexasRebel

Gearshifter
Joined
Mar 19, 2016
Threads
27
Messages
2,500
Reaction score
836
Location
between the mustard and the mayo
Vehicle(s)
2016 YZ GTPP - PP2
Switched the correct coils this time. Still P0301 and nothing else. Eight new fuel injectors on the way.

Found a misfire counter on my ODBLink app. The misfires seem to happen mostly on cold starts and at idle.
 

Sponsored

Torinate

Well-Known Member
Joined
Feb 18, 2018
Threads
82
Messages
1,913
Reaction score
852
Location
Ontario
Vehicle(s)
2016 GT Convertible
I'm hoping the injectors fix it!

Post up results...
 
OP
OP
BluePonyGT

BluePonyGT

Well-Known Member
Joined
Mar 24, 2018
Threads
39
Messages
540
Reaction score
268
Location
Seattle, WA
First Name
Corey
Vehicle(s)
2017 Grabber Blue GT Premium 6MT
Switched the correct coils this time. Still P0301 and nothing else. Eight new fuel injectors on the way.

Found a misfire counter on my ODBLink app. The misfires seem to happen mostly on cold starts and at idle.
What makes you think it's an injector problem? This is an ignition code, or a misfire. if the condition isn't optimal for ignition (ie too rich or too lean) then I would expect that to also throw a code on the fuel banks - separate code, and not just a misfire on #1.
 

Torinate

Well-Known Member
Joined
Feb 18, 2018
Threads
82
Messages
1,913
Reaction score
852
Location
Ontario
Vehicle(s)
2016 GT Convertible
Switched the correct coils this time. Still P0301 and nothing else. Eight new fuel injectors on the way.

Found a misfire counter on my ODBLink app. The misfires seem to happen mostly on cold starts and at idle.
OBD Link app. What OBD adapter are you using? Is this on iPhone or Android? Can you do logs as well?

I've been wanting to do something like this as well. Currently using FORScan on my laptop and it's not real easy to do logs etc for mode 6 data.

What's your set up?

Thanks.
 

TexasRebel

Gearshifter
Joined
Mar 19, 2016
Threads
27
Messages
2,500
Reaction score
836
Location
between the mustard and the mayo
Vehicle(s)
2016 YZ GTPP - PP2
What makes you think it's an injector problem? This is an ignition code, or a misfire. if the condition isn't optimal for ignition (ie too rich or too lean) then I would expect that to also throw a code on the fuel banks - separate code, and not just a misfire on #1.
Because this car is port injected, and the problem seems to be isolated at cylinder #1. I've ruled out the ignition coil by swapping #1 and #2. The next easy thing to do is to check the injector. Since these are OE with 144,000 miles, I figure it's about time to change them anyway. The other 7 cylinders seem to be firing just fine (otherwise I'd see a P0300 or another P030x), and this engine has a common fuel rail. That makes it seem unlikely it's a fuel pressure/volume issue.

My current hypothesis is the #1 injector is fouled or failing. It has good pressure and the PCM can't tell that it isn't firing other than the cylinder misfiring.

If the injectors don't remedy the situation, removing the manifold is next to check the actuator rod status... and if that looks good I have to start thinking about things like head gaskets and valves that aren't seating. I really hope it doesn't go that far.
 

TexasRebel

Gearshifter
Joined
Mar 19, 2016
Threads
27
Messages
2,500
Reaction score
836
Location
between the mustard and the mayo
Vehicle(s)
2016 YZ GTPP - PP2
OBD Link app. What OBD adapter are you using? Is this on iPhone or Android? Can you do logs as well?

I've been wanting to do something like this as well. Currently using FORScan on my laptop and it's not real easy to do logs etc for mode 6 data.

What's your set up?

Thanks.
OBDLink MX+

iPhone/iPad. It will log, I'm still playing with that feature. Saves desired data in a CSV file that you can import into R or Excel, or whatever your favorite data analysis software might be.

For this I had it logging Engine RPM and the misfire count. The increases in the misfire count line up pretty well with falling RPM and idle. misfires seem to disappear while the engine is wound up, and the count doesn't rise as quickly at operating temperature. While cold and idling they increase pretty quickly. I can't seem to find that log file though. It may not have saved.
 

Sponsored

Torinate

Well-Known Member
Joined
Feb 18, 2018
Threads
82
Messages
1,913
Reaction score
852
Location
Ontario
Vehicle(s)
2016 GT Convertible
OBDLink MX+

iPhone/iPad. It will log, I'm still playing with that feature. Saves desired data in a CSV file that you can import into R or Excel, or whatever your favorite data analysis software might be.

For this I had it logging Engine RPM and the misfire count. The increases in the misfire count line up pretty well with falling RPM and idle. misfires seem to disappear while the engine is wound up, and the count doesn't rise as quickly at operating temperature. While cold and idling they increase pretty quickly. I can't seem to find that log file though. It may not have saved.
Your misfires sound exactly like mine.
Idle and decel.
 

Torinate

Well-Known Member
Joined
Feb 18, 2018
Threads
82
Messages
1,913
Reaction score
852
Location
Ontario
Vehicle(s)
2016 GT Convertible
Thought you were having misfires on decel / falling rpm?
 

ice445

Well-Known Member
Joined
Apr 13, 2020
Threads
34
Messages
6,152
Reaction score
7,311
Location
Salt Lake City, UT
First Name
Ryan
Vehicle(s)
2020 Mustang GT 6MT
Because this car is port injected, and the problem seems to be isolated at cylinder #1. I've ruled out the ignition coil by swapping #1 and #2. The next easy thing to do is to check the injector. Since these are OE with 144,000 miles, I figure it's about time to change them anyway. The other 7 cylinders seem to be firing just fine (otherwise I'd see a P0300 or another P030x), and this engine has a common fuel rail. That makes it seem unlikely it's a fuel pressure/volume issue.

My current hypothesis is the #1 injector is fouled or failing. It has good pressure and the PCM can't tell that it isn't firing other than the cylinder misfiring.

If the injectors don't remedy the situation, removing the manifold is next to check the actuator rod status... and if that looks good I have to start thinking about things like head gaskets and valves that aren't seating. I really hope it doesn't go that far.
There's fancy ways to test injector balance with modern cars like this. One way is measuring the current draw when each injector fires. A little knowledge of the circuit and a current clamp (and a good scan tool to disable each injector one at a time), and bob's your uncle. I understand you may not have access to all of that stuff, but most people have access to a meter. If you ohm out the injector that you suspect is bad and the two next to it (to get a baseline), you can get a pretty good idea if that one is bad. Not sure what the spec for a good one is on this engine, but it's probably somewhere between 10 and 20 ohms. If you see like double or triple what the others are, then it's bad for sure.

You also may have cracked/deteriorated injector o-rings letting air past, especially since you said it's worse when the car is cold. The mileage is getting up there, that's a lot of heat cycles for a hot running engine.
 

Cobra Jet

Well-Known Member
Joined
Feb 12, 2015
Threads
710
Messages
16,282
Reaction score
18,048
Location
NJ
Vehicle(s)
2018 EB Prem. w/PP and 94 Mustang Cobra
Because this car is port injected, and the problem seems to be isolated at cylinder #1. I've ruled out the ignition coil by swapping #1 and #2. The next easy thing to do is to check the injector. Since these are OE with 144,000 miles, I figure it's about time to change them anyway. The other 7 cylinders seem to be firing just fine (otherwise I'd see a P0300 or another P030x), and this engine has a common fuel rail. That makes it seem unlikely it's a fuel pressure/volume issue.

My current hypothesis is the #1 injector is fouled or failing. It has good pressure and the PCM can't tell that it isn't firing other than the cylinder misfiring.

If the injectors don't remedy the situation, removing the manifold is next to check the actuator rod status... and if that looks good I have to start thinking about things like head gaskets and valves that aren't seating. I really hope it doesn't go that far.
Unless I missed it - I did see you swapped coils - but have you pulled any spark plugs yet to see condition/read them? I'd be curious to see the #1 plug condition compared to the others.
Sponsored

 
 




Top