P0300 codes drama

[BlueStang16]

I appreciate you all for the feedback. Lots of options. So here's what my research has yielded reading all the forums and sites related to issues like mine:

1.) Swap the intake (Gen2) manifold for the Gen3 Intake Manifold (2018+) with all the harnesses, and get a custom tune like Lund, but stay away from Bama, or

2.) Swap my intake with a GT350 intake and throttle body spacer and get a custom tune (same ending as above), or

3.) purchase a good, used Gen2 intake off eBay and just swap it out (but at what point does my current issue crop up with THAT intake?), or

4.) Swap mine for the VMP 2018 Intake Manifold and power pack (come with all the harnesses) and get a custom tune (as in 1 and 2), or

5.) Swap the Gen2 intake for the Ford Performance Gen3 Coyote Intake that says is a direct replacement, but some info says it does require a tune and others say it does not (even on the same website), so I am confused.

Anybody got a straight answer I can go with? Just want to buy the parts, get them on, and have this issue resolved (and prevent damaging the catalytic converter) and not have to worry about it again. Thanks in advance.

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[Cobra Jet]

Before you go swapping intakes…

Your S550 has miles on it - more than most on this forum (because most think an S550 will melt in the rain or look at their S550’s in the garage like a big 1:18 model in a box)….

Check this link and the threads in it:
https://www.mustang6g.com/forums/th...as-on-this-problem.208430/page-6#post-4171713

You have already went through the circle of replacing plugs and coils - it’s not that, and don’t continually throw parts at it. You have to do more digging on a modern day vehicle due to how ALL of the sensors are tied together to communicate back to the PCM. One freaking sensor that is on the outs or one wobbly unsteady part will cause downstream issues that sometimes replicates something stupid like a coil - but turns out it isn’t a coil….

The whole swapping intakes - to me, is a waste of time. The IMRC issue has BEEN an issue with Ford V8’s since its inception of design and concept that debuted with the Lincoln MK VIII when the 4.6 DOHC was replacing the pushrod 5.0 V8. That DOHC was then modified to create another variant that was born into the 1996 SVT Cobra 4.6 DOHC and carried forward into other SVY products down the line…. Then the DOHC 4.6 has morphed into the 5.0 Coyote platform (with all of its variants).

That whole IMRC system (from a functional standpoint) has been GARBAGE and has been nothing but headaches for ALL Mustang owners when it was incorporated since 1996. IMRC shaft failures, IMRC plate failures, IMRC sensor failures - it’s NOT new, it’s not something that just affects S550’s. Even the whole “IMRC delete” ideology - yes, you guessed it - started and was being done in 1996…

So swapping to a 2018+ intake isn’t going to solve the IMRC issue because it is still part of the Coyote design…. There have been 2018 owners referencing BS with the IMRC system as well.

It is the design of the IMRC system that is the failure point and so far - since 1996 to date - the ONLY options have been:
1) FIX the broken IMRC shaft as others have successfully done on this site

2) delete the IMRC

3) find another used intake w/good IMRC (then…. eventually replace when THAT fails)

4) Buy new Ford IMRC parts and sensors

So either until the aftermarket comes up with a much better, more robust IMRC system that isn’t prone to the failures it’s been seeing since 1996, those failures will continue OR Ford goes back to its vendor supplying the IMRC system and does a redesign to fix the problem.

Also to note:
When doing an IMRC delete, the “con” of it is, the engine looses its low end torque. Again this is a known fact that has been around since 1996…. Take a part of the function out that was designed into the entire operation and performance of the engine - and you’re going to experience a loss UNLESS there is another way to do it and not lose that element of low end torque.

There won’t be and has never been an NHTSA recall on the IMRC system - because it’s not a safety failure and does not severely impact the operation of the vehicle.

IMO -
Cheap plastic/ABS/Nylon should not be used in an application where the part(s) experience extreme heat and cool down cycles. This is a failure. Those parts should all be metal where and when they can be. In conjunction with those current plastic parts, thin metal rods should not be used in the same function where that rod is continually experiencing stress from daily use and the same heat cycles - it’s going to BREAK. The rod diameter needs to be larger and maybe even the composition of metal being used in the rod needs to be better to prevent the breakage.

/ jumping down off the podium … because IMRC BS hasn’t changed since ‘96….. and an intake swap is only a band-aid.

 

[BlueStang16]

Before you go swapping intakes…

Your S550 has miles on it - more than most on this forum (because most think an S550 will melt in the rain or look at their S550’s in the garage like a big 1:18 model in a box)….

Check this link and the threads in it:
https://www.mustang6g.com/forums/th...as-on-this-problem.208430/page-6#post-4171713

You have already went through the circle of replacing plugs and coils - it’s not that, and don’t continually throw parts at it. You have to do more digging on a modern day vehicle due to how ALL of the sensors are tied together to communicate back to the PCM. One freaking sensor that is on the outs or one wobbly unsteady part will cause downstream issues that sometimes replicates something stupid like a coil - but turns out it isn’t a coil….

The whole swapping intakes - to me, is a waste of time. The IMRC issue has BEEN an issue with Ford V8’s since its inception of design and concept that debuted with the Lincoln MK VIII when the 4.6 DOHC was replacing the pushrod 5.0 V8. That DOHC was then modified to create another variant that was born into the 1996 SVT Cobra 4.6 DOHC and carried forward into other SVY products down the line…. Then the DOHC 4.6 has morphed into the 5.0 Coyote platform (with all of its variants).

That whole IMRC system (from a functional standpoint) has been GARBAGE and has been nothing but headaches for ALL Mustang owners when it was incorporated since 1996. IMRC shaft failures, IMRC plate failures, IMRC sensor failures - it’s NOT new, it’s not something that just affects S550’s. Even the whole “IMRC delete” ideology - yes, you guessed it - started and was being done in 1996…

So swapping to a 2018+ intake isn’t going to solve the IMRC issue because it is still part of the Coyote design…. There have been 2018 owners referencing BS with the IMRC system as well.

It is the design of the IMRC system that is the failure point and so far - since 1996 to date - the ONLY options have been:
1) FIX the broken IMRC shaft as others have successfully done on this site

2) delete the IMRC

3) find another used intake w/good IMRC (then…. eventually replace when THAT fails)

4) Buy new Ford IMRC parts and sensors

So either until the aftermarket comes up with a much better, more robust IMRC system that isn’t prone to the failures it’s been seeing since 1996, those failures will continue OR Ford goes back to its vendor supplying the IMRC system and does a redesign to fix the problem.

Also to note:
When doing an IMRC delete, the “con” of it is, the engine looses its low end torque. Again this is a known fact that has been around since 1996…. Take a part of the function out that was designed into the entire operation and performance of the engine - and you’re going to experience a loss UNLESS there is another way to do it and not lose that element of low end torque.

There won’t be and has never been an NHTSA recall on the IMRC system - because it’s not a safety failure and does not severely impact the operation of the vehicle.

IMO -
Cheap plastic/ABS/Nylon should not be used in an application where the part(s) experience extreme heat and cool down cycles. This is a failure. Those parts should all be metal where and when they can be. In conjunction with those current plastic parts, thin metal rods should not be used in the same function where that rod is continually experiencing stress from daily use and the same heat cycles - it’s going to BREAK. The rod diameter needs to be larger and maybe even the composition of metal being used in the rod needs to be better to prevent the breakage.

/ jumping down off the podium … because IMRC BS hasn’t changed since ‘96….. and an intake swap is only a band-aid.

Thanks, man. I read the post on the link. Replacing the VCT solenoids on both sides of the engine with Ford Performance ones was the first things I did when I got the car. Had CEL and severe stalling-at-stops issues. The FP ones run so much better than the stock did.

Again, true misfires are seldom and random. Have new plugs and coils, no vacuum leaks or bad seals, no cylinder issues. My mechanic even said he doesn't think it's the IMRC because it's not giving indications. So I am stumped, but EVERYTHING at this point, everything seems to indicate a failing/failed IMRC on the manifold.

However, am I overlooking SENSORS? Which sensors other than the ones indicating the misfires should/could I be looking at?

 

[Cobra Jet]

Crank sensor - pull it and check the condition of the sensor itself, but also ohm spec it and see what it reads. Is it within the Ford spec? Is it much higher +/- than the Ford spec, if so, it’s done. Also check the wires going into the plug that plugs onto the sensor. Make sure the pins are in it tight and don’t pull out and check the wire under the conduit for any damage.

MAF - common culprit for engine operation blips. Also check to make absolutely sure that all clamps and hoses along the MAF/air intake path are totally secure.

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