P0300 & P0308

[Red65]

On the interstate headed home last night and the check engine light popped up. At this point I’m thinking “oh no, what now”. (Let it be known that I have already had to replace the original engine at 3500 miles for the ticking issue and a subtle double knock coming from the wristpins. New shortblock also ticks currently at 8000 miles) So I hook it up to my buddy’s OBD2 reader and these two codes popped up. A quick google search leads me to believe that the IMRC’s are pooched and apparently, dealerships have a hard time diagnosing cars with these codes since they immediately start swapping coil packs and spark plugs.

I tell you, this car strains my nerves sometimes. It will be 100% warrantied so at least my wallet isn’t hurting. I’m curious to hear yalls stories regarding these two codes and possibly some tips to reduce the downtime on the car.

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[usgiorgi]

My dealer immediately diagnosed it as the IMRC. In the work order, it said that the tech hooked it up to a diagnostics tool and took it for a drive and saw that the runner control valves weren't working.
The only annoying part about that visit was that they didn't give me a loaner until they lost my keys and couldn't give me my car...Took about 2 days to get the part in and do the work.

 

[RIBS]

There is a special service bull item from Ford on this exact issue, tell the Dealer to search recent Ford notices....last 2 or 3 months...

 

[Red65]

There is a special service bull item from Ford on this exact issue, tell the Dealer to search recent Ford notices....last 2 or 3 months...

Do you happen to know the TSB #?

 

[RIBS]

Review this:
https://ford.oemdtc.com/3833/illumi...tc-p0300-through-p0308-2015-2017-ford-mustang

 

[NYDP77]

Did you lose power? Mine turned out to be 7th and 8th cylinder misfire. The dealer first thought it was a bad cat converter causing the problem, ultimately they had to replace the intake manifold. That fixed it has been fine for over a year.

 

[CEHollier]

Does this affect the GT 350 manifolds? I did a swap.

 

[SamB11]

Did you lose power? Mine turned out to be 7th and 8th cylinder misfire. The dealer first thought it was a bad cat converter causing the problem, ultimately they had to replace the intake manifold. That fixed it has been fine for over a year.

Having this issue right now. Since it has been recalled and I still have my warranty, I will be bringing it in the dealer this week!!!

 

[Jetnoise]

On the interstate headed home last night and the check engine light popped up. At this point I’m thinking “oh no, what now”. (Let it be known that I have already had to replace the original engine at 3500 miles for the ticking issue and a subtle double knock coming from the wristpins. New shortblock also ticks currently at 8000 miles) So I hook it up to my buddy’s OBD2 reader and these two codes popped up. A quick google search leads me to believe that the IMRC’s are pooched and apparently, dealerships have a hard time diagnosing cars with these codes since they immediately start swapping coil packs and spark plugs.

I tell you, this car strains my nerves sometimes. It will be 100% warrantied so at least my wallet isn’t hurting. I’m curious to hear yalls stories regarding these two codes and possibly some tips to reduce the downtime on the car.

What year car do you have?

 

[UglyMutt]

A little late on this thread but do you guys know if this is covered under the 5 year powertrain warranty?

 

[Cobra Jet]

Here ya go, threads were posted by other members for same bank of codes, it may help those seeking more info:

https://www.mustang6g.com/forums/threads/cel-p0300-and-p0308.70926/

https://www.mustang6g.com/forums/th...0-or-p0308-codes-read-me.115108/#post-2608923

 

[Lincolnzz]

Did you lose power? Mine turned out to be 7th and 8th cylinder misfire. The dealer first thought it was a bad cat converter causing the problem, ultimately they had to replace the intake manifold. That fixed it has been fine for over a year.

How is it doing now? In November 2019 I had my intake manifold replaced under power train warranty due to frozen bank 2 imrc.

Now in march 2022 I’ve gotten the flashing cel, stumble at low rpms, and what sounds like a knock. Code p0300 and p306. Feels like the same issue as before, but it’s now at 65k miles so I suppose it could be my stock plugs going bad, but still seems early. I’d almost bet on my replacement manifold having imrc problems.
I’m at 65k so I’m not going to the dealer to pay a ton for them to put another oem2017 manifold on and have it break in another 15k miles like the last one.

I suppose my next steps are to check the plugs and then find a buddy that can help me install a 2018+ manifold / air box.

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