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Big random drops in fuel trim *pic

  • Pharmdviper
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1 year 3 weeks ago #67160 by Pharmdviper
Big random drops in fuel trim *pic was created by Pharmdviper
2008 gx470 runs great but at speed I’m getting a hesitation at random times. I hooked up my scanner and no codes but when it happens my fuel trims will run WAY rich for a second and then go back to normal…any ideas? I have no codes
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  • Tyler
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1 year 3 weeks ago #67161 by Tyler
Replied by Tyler on topic Big random drops in fuel trim *pic
My WAG would be that there's something wrong with the vehicle that causes it to hesitate, AND briefly lose communication with the scan tool. -85.9% isn't a rational value for short or long term fuel trims. Toyota/Lexus products don't give the trims that much range of adjustment. I'm guessing that -85.9% isn't a true reading from the vehicle, but actually just the minimum value the BlueDriver can display for a given fuel trim PID.

On your next test drive, I'd suggest watching a few other PIDs in addition to the trims. Engine speed, module voltage, coolant temp and maybe Distance to DTC Clear. See if these other PIDs experience the same drops during your hesitation.

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