Running rough cold....an old thread dug up

[ScottsGT]

Remember this thread?
http://www.mustang6g.com/forums/showthread.php?t=24730

Ever since I bought my car back on Nov. 5th, 2014 I have been running 91 octane gas. After several threads on the subject of throwing good money away at buying 91 and not 87, I figured what the hell, I'll give it a try.

And have I ever noticed a big difference! Now my cold morning drives are almost a thing of the past. For some reason the higher octane made the throttle very jumpy and hesitant. (Read the thread, hard to describe)
Now I can hardly feel the hesitation and it is much smoother until it is fully warmed up.
Doing the math, I've spent almost/around $500 more on premium :headbonk: and it all around runs better on the cheap stuff.

FYI, two tanks through it now and the mileage is still the same.

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[SnoopisTDI]

Interesting!

I was considering changing to 87 for the winter, but we're already starting to warm up again. I'll definitely keep that thought in the back of my mind though.

 

[Blue Horse]

Remember this thread?
http://www.mustang6g.com/forums/showthread.php?t=24730

Ever since I bought my car back on Nov. 5th, 2014 I have been running 91 octane gas. After several threads on the subject of throwing good money away at buying 91 and not 87, I figured what the hell, I'll give it a try.

And have I ever noticed a big difference! Now my cold morning drives are almost a thing of the past. For some reason the higher octane made the throttle very jumpy and hesitant. (Read the thread, hard to describe)
Now I can hardly feel the hesitation and it is much smoother until it is fully warmed up.
Doing the math, I've spent almost/around $500 more on premium :headbonk: and it all around runs better on the cheap stuff.

FYI, two tanks through it now and the mileage is still the same.

Something is WRONG with your car,that is not normal !!!!!!!

 

[GDP]

Wut? Correlation does not equal causation. I'm running 93 Shell gas no issues.

 

[abuch91]

Have you checked your plugs? I run 93 all day no issues.

 

[lazarus870]

Oddly enough I seem to have a smoother engine and more responsiveness with 87 from Chevron than I do from Esso 91.

 

[3450]

Wut? Correlation does not equal causation. I'm running 93 Shell gas no issues.

Yeah, something else is probably the culprit. I only run 91/93, and I've never had issues in the cold. It was -7f this past weekend (without windchill) and car was fine.

Sent from my Nexus 6P

 

[GTBOB]

Lower octane is a faster burning fuel. Your car seems to like it.

 

[NewTekBuzz]

Hmmm I remember that thread! Ha
I am running Lund 93 now or I would give the 87 a try... Guess I could tune back to stock
That's just crazy

 

[kn7671]

Go to the Ford dealer and ask them if there a calibration update for your PCM by VIN. My car has been finicky with in cold weather too and needed a calibration update along with some other update for the PCM just to be able to accept the new calibration. It seemed to fix about 75% of my cold weather oddities.

 

[Chameleon]

opcorn:

 

[50hhh]

I find that 67 is the way to go.

 

[L8APEX]

I had no problem with 91, 93 or 94

 

[jasonstang]

You might be right on very cold situations, high octane gas just harder to ignite than lower octane. However, the difference between 87 and 91 is probably very minimal.

 

[ScottsGT]

Go to the Ford dealer and ask them if there a calibration update for your PCM by VIN. My car has been finicky with in cold weather too and needed a calibration update along with some other update for the PCM just to be able to accept the new calibration. It seemed to fix about 75% of my cold weather oddities.

I'll do this! Thanks.

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