3 days ago
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Posted On: October 13th 2026, 02:11 pm
Gen V LT Owners! Here's something to watch for.
Several times a year, customers tell us they feel a hiccup in the upper RPM range just before a shift.
And they're right!
In many cases, the A/C is still on during the pull. When the A/C clutch cycles, the ECM can use torque-management spark advance to momentarily pull timing. That sudden reduction in timing can feel like a hiccup, even though there isn't necessarily a mechanical problem or a misfire.
The scanner screenshot shows the brief timing dip we're talking about.
There are calibration options to disable A/C operation above a specified throttle percentage or engine RPM, but our recommendation is simple: make a habit of turning the A/C off before a WOT pull or track pass.
That also helps avoid A/C condensation dripping water at the track.
Before assuming the engine is misfiring or the transmission is acting up, check the log and verify whether A/C clutch activity lines up with the event.
Several times a year, customers tell us they feel a hiccup in the upper RPM range just before a shift.
And they're right!
In many cases, the A/C is still on during the pull. When the A/C clutch cycles, the ECM can use torque-management spark advance to momentarily pull timing. That sudden reduction in timing can feel like a hiccup, even though there isn't necessarily a mechanical problem or a misfire.
The scanner screenshot shows the brief timing dip we're talking about.
There are calibration options to disable A/C operation above a specified throttle percentage or engine RPM, but our recommendation is simple: make a habit of turning the A/C off before a WOT pull or track pass.
That also helps avoid A/C condensation dripping water at the track.
Before assuming the engine is misfiring or the transmission is acting up, check the log and verify whether A/C clutch activity lines up with the event.
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