21 Mustang GT Check Engine Light Under Hard Acceleration/Cornering and Low Fuel.

David Darius

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Hey guys, had a small and hopefully resolved issue come up on my new 2021 Mustang GT Convertible with under 1000 miles. Recently, had four people in the car and gave it a little gas, 4-5,000 RPM max into a corner and then for a few seconds, maybe 30 or less, my check engine light started flashing and then turned off. I only had about 20 miles of range/fuel at that moment.

The FordPass app messaged me minutes later stating that a warning light was triggered by a possible engine misfire or poor fuel condition. I did not feel or hear any possible engine misfire and would not have known anything happened if not for the flashing check engine light.

My thinking is that having been low on fuel and having accelerated hard into a corner, that perhaps the fuel pump or system felt it had less fuel available given the G forces moving fuel around and triggered the light which then turned off when I let off the gas. I did refuel the car after that and with some similar driving, did not have the light come back on the next few days. Well, it only flashes when I turn on the electrical/accessory power and not the gas engine and then turns off immediately when the gas engine is on.

Just today, I also received my monthly FordPass vehicle diagnostics report which showed no problems. Local Ford dealer said to have it checked out at next service if the light is gone now.

Has anyone here had a similar issue or have any thoughts about this? Let me know, thanks!

P.S. Car has been driven moderately hard as new, has not been redlined or abused much, lol.

-Dave
 

Dino Dino Bambino

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Your CEL came on because your fuel pump was momentarily starved of fuel as you were taking a corner. Allowing the fuel level to drop that low is completely unnecessary and risks burning out the fuel pump. My low fuel warning light comes on when the range is 50 miles to empty but I routinely add fuel as soon as the fuel gauge needle drops below 1/4. At 1/4 tank my on board computer usually shows a range of about 80 miles.
 

Olerodder

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Hey guys, had a small and hopefully resolved issue come up on my new 2021 Mustang GT Convertible with under 1000 miles. Recently, had four people in the car and gave it a little gas, 4-5,000 RPM max into a corner and then for a few seconds, maybe 30 or less, my check engine light started flashing and then turned off. I only had about 20 miles of range/fuel at that moment.

The FordPass app messaged me minutes later stating that a warning light was triggered by a possible engine misfire or poor fuel condition. I did not feel or hear any possible engine misfire and would not have known anything happened if not for the flashing check engine light.

My thinking is that having been low on fuel and having accelerated hard into a corner, that perhaps the fuel pump or system felt it had less fuel available given the G forces moving fuel around and triggered the light which then turned off when I let off the gas. I did refuel the car after that and with some similar driving, did not have the light come back on the next few days. Well, it only flashes when I turn on the electrical/accessory power and not the gas engine and then turns off immediately when the gas engine is on.

Just today, I also received my monthly FordPass vehicle diagnostics report which showed no problems. Local Ford dealer said to have it checked out at next service if the light is gone now.

Has anyone here had a similar issue or have any thoughts about this? Let me know, thanks!

P.S. Car has been driven moderately hard as new, has not been redlined or abused much, lol.

-Dave

I had quite a few issues with fuel lights and running out fuel more than once because of the fuel transfer module that pumps fuel from one saddle tank to the other, and also when driving with low fuel levels. Personally, I would never let the tank get less than 1/2 to 3/8 empty before gassing up. My initial issue was when the gauge would show 1/4 or less I'd be driving along and all of sudden the gauge would drop to E and the 5 mile warning would appear, which meant if I didn't find a gas station with 10 miles or so I was going to be sitting beside the road. This happened 3 times and stranded me 15 miles from civilization. Ford did come to the rescue and they put it on a flatbed and straight to the dealer. Once when it ran out of gas, I put 2 gallons in it and drove it to the gas station and it only took 9 gallons to fill it up.
 

86GT351

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Your CEL came on because your fuel pump was momentarily starved of fuel as you were taking a corner. Allowing the fuel level to drop that low is completely unnecessary and risks burning out the fuel pump. My low fuel warning light comes on when the range is 50 miles to empty but I routinely add fuel as soon as the fuel gauge needle drops below 1/4. At 1/4 tank my on board computer usually shows a range of about 80 miles.
This
 

David Darius

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Your CEL came on because your fuel pump was momentarily starved of fuel as you were taking a corner. Allowing the fuel level to drop that low is completely unnecessary and risks burning out the fuel pump. My low fuel warning light comes on when the range is 50 miles to empty but I routinely add fuel as soon as the fuel gauge needle drops below 1/4. At 1/4 tank my on board computer usually shows a range of about 80 miles.

Yes, I will be more careful from now on.
 

Juice

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I have been on track till the low fuel light came on. Hard cornering, and no CEL. I feel some of this info is a myth. If 11 gallons filled the car from empty, there is something not quite right.
I believe when my low fuel light comes on, there is about 2 gallons left, and I have gone up to 30 miles (not on track) after light came on to date.
That has been my experience.
I should find out just how far I can go past the low fuel, with a 5 gallon can in trunk, drive till it runs out. I have no worries doing that once. Shit, still running the original fuel pump. lol
 

JEWC_Motorsports

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Most of us that switch from e85 to 93 run down to 1 mile left and never have issues. The 21's may be different though. Cant even tune them yet.
 

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