06 E38 LS2 Corvette with 6l80e unwanted throttle blip on downshift

The engine is modified with big cam, heads and so on, the engine and transmission tune have also been modified. The problem is when decelerating to a stop in drive as the car downshifts into 2nd and 1st gear the engine rpm goes up just just enough to cause the car to jerk forward which can be irritating and dangerous. I don't think it is the transmission shifting I think the throttle is making an adjustment. It does not happen in sport mode when using the paddle shift. Ideas anyone?

You drilled the throttle didn't you?

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Originally Posted by macca_779

You drilled the throttle didn't you?

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I cant speak for the OP, but all TBSS' do this stock from GM with the 4L70E. Needless to say, it is HIGHLY irritating and unsafe. As you are coming to a stop, the trans downshifts from 2->1 and jerks the truck forward. This happens around 2-3mph, so just as you are starting to remove full pressure from the brake pedal.

But if it doesnt do it in Sport mode, to me that points at a tune issue/table. Post a log of it happening and the tune.

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Originally Posted by macca_779

You drilled the throttle didn't you?

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No didn't drill the throttle.

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Originally Posted by RD in SD

No didn't drill the throttle.

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Interesting. Only seen this happen when guys over drill the throttle