Surging at 2250RPMs, tune related?

should give them a call tomorrow

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Definitively going to do that.

You should never run, 89 Octane in a 2011 GT

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I always run 93 in it regardless of what tune is loaded, even when it was bone stock. Running lower octane fuels just feels wrong somehow to me.

making good power otherwise? this a sudden thing?

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The car seems to be running great other than that. I just really noticed it today cause I went on a road trip and drove the car @ about 77MPH which is right at 2250RPMs with my 3:55s. It could have been doing it before but since I don't drive at that speed often I wouldn't of seen it. So when I got home I change the tune to my 93 octane performance tune and it seemed a lot better then I tried the 89 street tune which seemed a little better than the 93 performance tune.

You can see the tach jump a little when it's doing it BTW

ITLRUN said:

You should never run, 89 Octane in a 2011 GT. I don't care what anyone says, or what tune they put in. Any car that's running over 400HP, should always run on premium fuel. I know there's parts of the Country, that don't have 93 Octane available. But if it's available to you, run it at all times I do and have no issues what so ever. I run 93 Octane in all my cars, and sometimes mix with race gas depending on the car and they run very strong without any misses, Mike. :nono::nono:

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so i guess 87 is not a good idea? really.

beers

ITLRUN said:

You should never run, 89 Octane in a 2011 GT. I don't care what anyone says, or what tune they put in. Any car that's running over 400HP, should always run on premium fuel. I know there's parts of the Country, that don't have 93 Octane available. But if it's available to you, run it at all times I do and have no issues what so ever. I run 93 Octane in all my cars, and sometimes mix with race gas depending on the car and they run very strong without any misses, Mike. :nono::nono:

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This is just plain wrong. A stock car under normal driving is ok. The engine is nowhere near 400HP at highway speeds. Please don't take this advice... you don't know more than the Ford engineers. If you mod your car, well thats another thing...

Guys I spoke to the staff at Bama and they told me that there was a new revision of the tunes that addressed some driveability issues. So far I've tried the 91 octane street tune and the issue is gone I'm going to load up the performance tune next and see how it does. I checked my gas mileage at 60 and was getting 27.3 and at 78 I was getting 22.1 which makes me happy. Thanks for all the advice.

ITLRUN said:

You should never run, 89 Octane in a 2011 GT. I don't care what anyone says, or what tune they put in. Any car that's running over 400HP, should always run on premium fuel. I know there's parts of the Country, that don't have 93 Octane available. But if it's available to you, run it at all times I do and have no issues what so ever. I run 93 Octane in all my cars, and sometimes mix with race gas depending on the car and they run very strong without any misses, Mike. :nono::nono:

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I agree with you in the sense of the peace of mind. I most certainly run 93 in my car bone stock. HOWEVER, there have been plenty of people running 87. The Coyote's computer is smart enough to adjust its firing for 87 on the factory software.

My car very mildly does the same surging. Seems to be pretty common to those that are sensitive to what thier cars are doing. I read something somewhere that said the surging is because that is around when the TiVCT starts to kick in and adjust timing. I know I don't have hard data for you but this was a concern of mine when I first got the car so I did some research and recommend you attempt the same. It would seem to make a good case that s tune would exasperate the surging too. Take it for what it's worth, I could easily be wrong

I guess what I forgot to mention is that the surge didn't happen under a load it was just noticeable under very light load. Like cruising slow through my neighborhood or on the highway with the cruise set. I did datalog the car and saw no knock under these conditions.

Whatever it was the updated tune fixed it.