GT S550 Intake Manifolds - Are they really a common problem?

[Dseck63]

Well I hope I'm in the right section since it's mostly technical advice here for mods but I have a question about oem intake manifolds. Are they a common problem? The reason I ask is I recently had P0300 and P0302 pop up which is a random cylinder misfire and a cylinder 2 misfire. My car only has 46k on it but I changed the plugs and cleared it only to drive another 75 miles or so and boom its back on. Ended up sending it into ford this time and got the call today that they will be replacing the intake manifold but needed to order one and I would get my car back Tuesday. I asked the service adviser if it was the runners that were stuck and he insisted not knowing and wouldn't tell me and wanted to get off the phone.

While I'm covered for this under warranty I want to know what went wrong and if Ford has an issue with the manifolds have they addressed it. I did see one other person with my SAME EXACT mileage have this happen with the same result. Could be a coincidence but in his thread nothing was said after it was repaired and picked up. Any thoughts? Otherwise I'll be bracing myself in about another 40k for this to happen again unless I boost it or upgrade to the stage 3 performance pack..

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[kent0464]

Well I hope I'm in the right section since it's mostly technical advice here for mods but I have a question about oem intake manifolds. Are they a common problem? The reason I ask is I recently had P0300 and P0302 pop up which is a random cylinder misfire and a cylinder 2 misfire. My car only has 46k on it but I changed the plugs and cleared it only to drive another 75 miles or so and boom its back on. Ended up sending it into ford this time and got the call today that they will be replacing the intake manifold but needed to order one and I would get my car back Tuesday. I asked the service adviser if it was the runners that were stuck and he insisted not knowing and wouldn't tell me and wanted to get off the phone.

While I'm covered for this under warranty I want to know what went wrong and if Ford has an issue with the manifolds have they addressed it. I did see one other person with my SAME EXACT mileage have this happen with the same result. Could be a coincidence but in his thread nothing was said after it was repaired and picked up. Any thoughts? Otherwise I'll be bracing myself in about another 40k for this to happen again unless I boost it or upgrade to the stage 3 performance pack..

Yes, a quick search showed that the IM cracking is an issue and that the one they swap in for the damaged one has a different part number, so it’s some thing Ford is aware of.

 

[kevinvan6000]

Had the same thing happen on my 17 GT. Mine had 42k km (26k miles) when mine went bad. IMRC shaft was broken on mine and the valves were stuck. Was replaced under warranty. I'm going to swap to an 18+ intake and lock out the IMRCs one mine soon.

 

[Dseck63]

In this case I'm glad it went when it did. I haven't been told specifically that the imrc shaft broke but I wouldn't be surprised if this is the culprit.

 

[2morrow]

I have a similar issue going on and have suspected the same end result however I have a ported IM with custom tunes so Ford coverage is out of the question. When I find out more I'll report back.

 

[Shifting_Gears]

Yes it’s a fairly common issue. Mine failed around 7k. One of the shafts broke and the car would misfire under light throttle acceleration or cruising. I had similar codes.

 

[Muff Muff]

Mine went at 14k miles a little over 2 years ago. I had it replaced under warranty, and at 37.5k miles now, I've had no more problems. I'm fairly certain the 15-17 manifold received an updated part number to reflect changes made.

 

[Cobra Jet]

The intake cracking is only 1 problem... then there is the possibility of the IMRCs failing, which is a totally separate problem, BUT still requires the upper intake manifold to be replaced.

Ford SSM:

 

[dope]

I am having exactly the same issue as OP. Check engine light comes on at 46K miles so I brought it to my local mechanic. They take a look and initially think the issue was bad gas so they do a BG fuel system service and replace my spark plugs. 50 miles later the check engine light comes back on. I take the car back to the shop and they tell me my GT had multiple cylinder misfires. Cylinder 8 had a bunch of misfires in particular. I had the P0308 diagnostic code. They research the issue and tell me that the likely cause is the IMRC shaft failing since it's the most common cause of a P0308 code. I decline to have my mechanic take apart the Intake Manifold to confirm the exact issue. I contact Ford and they tell me to bring it into the dealership so a Ford tech can diagnose the issue. The service advisor tells me that his tech confirmed that the IMRC shaft is broken and recommends an intake manifold replacement. I contact Ford again and they opens a case for me and I finally receive a call from the customer experience rep in charge of my case. They tell me they can likely cover a partial amount for the repair, but that they need to speak with the service advisor first to collect some more information before they can confirm how much they can cover. My car is just outside of the 5 year warranty (purchased my 2016 slightly more than 5 years ago). Hoping they can cover most of the cost for the repairs since it's a known issue (there's a TSB as the previous poster mentioned) and the plastic IMRC shaft breaks frequently at low mileage.

 

[SensesFail]

Yep, 20k miles. Replaced intake manifold with a new one and then did an IMRC delete and tuned for it.

 

[Andrew@Lethal]

Well I hope I'm in the right section since it's mostly technical advice here for mods but I have a question about oem intake manifolds. Are they a common problem? The reason I ask is I recently had P0300 and P0302 pop up which is a random cylinder misfire and a cylinder 2 misfire. My car only has 46k on it but I changed the plugs and cleared it only to drive another 75 miles or so and boom its back on. Ended up sending it into ford this time and got the call today that they will be replacing the intake manifold but needed to order one and I would get my car back Tuesday. I asked the service adviser if it was the runners that were stuck and he insisted not knowing and wouldn't tell me and wanted to get off the phone.

While I'm covered for this under warranty I want to know what went wrong and if Ford has an issue with the manifolds have they addressed it. I did see one other person with my SAME EXACT mileage have this happen with the same result. Could be a coincidence but in his thread nothing was said after it was repaired and picked up. Any thoughts? Otherwise I'll be bracing myself in about another 40k for this to happen again unless I boost it or upgrade to the stage 3 performance pack..

Sounds like you might need to invest in some IRMC lockouts

15-17 GT https://www.lethalperformance.com/mmr-cmcv-lock-outs-for-2015-2017-mustang-intake-manifolds.html

18+ GT MMR 478911 2018+ Mustang CMCV Runner control LOCK OUT kit (MMR-478911)

Available here from Lethalperformance

 

[VisceralSyn]

IMRC seized up on my 17 GT at around 35K mi, and it was a known issue at that time. Dealership replaced the intake manifold.

 

[jacknifetoaswan]

I am having exactly the same issue as OP. Check engine light comes on at 46K miles so I brought it to my local mechanic. They take a look and initially think the issue was bad gas so they do a BG fuel system service and replace my spark plugs. 50 miles later the check engine light comes back on. I take the car back to the shop and they tell me my GT had multiple cylinder misfires. Cylinder 8 had a bunch of misfires in particular. I had the P0308 diagnostic code. They research the issue and tell me that the likely cause is the IMRC shaft failing since it's the most common cause of a P0308 code. I decline to have my mechanic take apart the Intake Manifold to confirm the exact issue. I contact Ford and they tell me to bring it into the dealership so a Ford tech can diagnose the issue. The service advisor tells me that his tech confirmed that the IMRC shaft is broken and recommends an intake manifold replacement. I contact Ford again and they opens a case for me and I finally receive a call from the customer experience rep in charge of my case. They tell me they can likely cover a partial amount for the repair, but that they need to speak with the service advisor first to collect some more information before they can confirm how much they can cover. My car is just outside of the 5 year warranty (purchased my 2016 slightly more than 5 years ago). Hoping they can cover most of the cost for the repairs since it's a known issue (there's a TSB as the previous poster mentioned) and the plastic IMRC shaft breaks frequently at low mileage.

If you're somewhat handy, you can replace the intake manifold fairly easily. I have a 2016 intake manifold with functional IMRCs that I would let go for cheap to get it out of my garage.

JR

 

[accel]

I'm suspectingthere's minor air leak in my IM. There's very minor random idle instability that was not here before. And I'm getting engine detonation on Power Pack level 2. Rolling back to stock there's no detonation, but I'm suspection ltft shft values are a little off norm.

Also, while on the freeway driving constant speed AFR gauge is not staying in place but acting more like a pandulum in the 13.5-14.5 range.

Which inexpensive obd tool lets you record STFT + LTFT?

 

[SensesFail]

I'm suspectingthere's minor air leak in my IM. There's very minor random idle instability that was not here before. And I'm getting engine detonation on Power Pack level 2. Rolling back to stock there's no detonation, but I'm suspection ltft shft values are a little off norm.

Also, while on the freeway driving constant speed AFR gauge is not staying in place but acting more like a pandulum in the 13.5-14.5 range.

Which inexpensive obd tool lets you record STFT + LTFT?

Are you hearing or feeling the detonation? Or did you come across positive knock in logs?

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