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Discussion Starter · #1 ·
While passing a semi on an interstate recently, my car's CEL flashed 4 times. I scanned the car for any stored codes and nothing. This was about 1000 miles ago and it never came back.


I know this most likely means a brief misfire. Anyone else had this happen?
 

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Discussion Starter · #4 ·
Normally I run 87 only, as this is what the car is tuned for from the factory and I am stock. However, this happened to be on a tank of 93 since it was the middle of the night on I-16 in rural south GA where the only open station was sold out of 87. It happened within 10-20 miles of the fill up.


Possible it was just a bit of bad gas. The rest of the tank did fine, no different than the car ever behaves. And it's been fine since. Car had 13,500 miles at the time and has 14,900 now. Either way, it's under warranty, I suppose.
 

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Definitely a misfire. This happened on my car once, and I took it to Hyundai (it's actually sitting there as I type this). They determined ignition coil 1 needed replacing.

I found the code with my ODBII bluetooth scanner and Torque listed under the pending codes.
 

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Normally I run 87 only, as this is what the car is tuned for from the factory and I am stock.
This simply isn't true. It isn't "tuned" to run 87. It's "tuned" so you can run terrible gas if you want. The ECU will detect knock on 87 and retard timing so the car doesn't run like ****. It can do the reverse when running 91 or better - detect that there isn't knock and advance timing so the car runs better. That's precisely what octane ratings are - a measurement of a fuel's resistance to knock. They basically know that most of their customers are cheap and will run the shittiest, cheapest gas they can find, so they set the adaptive ECU up accordingly. That is not, however, how the car will run best.
 

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This simply isn't true. It isn't "tuned" to run 87. It's "tuned" so you can run terrible gas if you want. The ECU will detect knock on 87 and retard timing so the car doesn't run like ****. It can do the reverse when running 91 or better - detect that there isn't knock and advance timing so the car runs better. That's precisely what octane ratings are - a measurement of a fuel's resistance to knock. They basically know that most of their customers are cheap and will run the shittiest, cheapest gas they can find, so they set the adaptive ECU up accordingly. That is not, however, how the car will run best.
I remember I went back and forth with you on this issue a while back. I have been a running 93 since then and the car has run a ton better especially in the heat. So foot in mouth on that one.
 
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Flashing check engine light is indicating a catalytic damaging event is occurring. This usually is from a misfire of some sort. If it hasn't returned with no codes I wouldn't worry about it until it happens more frequently or at least a code is found. Happy motoring.
 

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Discussion Starter · #11 ·
This simply isn't true. It isn't "tuned" to run 87. It's "tuned" so you can run terrible gas if you want. The ECU will detect knock on 87 and retard timing so the car doesn't run like ****. It can do the reverse when running 91 or better - detect that there isn't knock and advance timing so the car runs better. That's precisely what octane ratings are - a measurement of a fuel's resistance to knock. They basically know that most of their customers are cheap and will run the shittiest, cheapest gas they can find, so they set the adaptive ECU up accordingly. That is not, however, how the car will run best.

This is simply true. The stock tune is for 87 - the power ratings are for 87. There was a post on this forum by a vendor who was experimenting with tuning who also said the stock tune was clearly for regular.


I'm aware of what octane is, what it does, etc - no amateur at this. I've had cars that require premium and I have always used it when required. This one is not one of those and I have experimented and it makes zero detectable difference in MPG or performance (since again it is tuned for 87).


But we can disagree about this forever. The car had this episode while running 93. So far it has not returned. :D
 

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...and it makes zero detectable difference in MPG or performance (since again it is tuned for 87).
It also, as numerous people have said numerous times, pulls timing more significantly while running regular. As seen in multiple datalogs. Feeling it is one thing, see it is another.
 

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This is simply true. The stock tune is for 87 - the power ratings are for 87. There was a post on this forum by a vendor who was experimenting with tuning who also said the stock tune was clearly for regular.


I'm aware of what octane is, what it does, etc - no amateur at this. I've had cars that require premium and I have always used it when required. This one is not one of those and I have experimented and it makes zero detectable difference in MPG or performance (since again it is tuned for 87).


But we can disagree about this forever. The car had this episode while running 93. So far it has not returned. :D
Correct - premium isn't required. But the car will run better with it. It's not even a question. If you know what octane is and you understand what an adaptive ECU is then you know what I'm talking about and are just being obtuse.
 
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