Throttle body not opening 99%

[J-CUE]

I have a 2010 Silverado Z71, and Iv'e noticed that after a PCM flash, the throttle will open all of the way and read 99% until one engine cycle.
After a drive, engine shut off, left to sit for a short time, then restarted and driven, it will only read 38.7% when going WOT.
With ignition on, engine off, it will read 99% but, when the engine is started, it will only read 38.7%.
I'm not on my computer to post a tune but, FYI its a stock truck with a pretty much stock tune. The only thing Iv'e done so far is decreased some trans torque management and changed the shift points.
Does anyone know if anything can be changed to allow the throttle to open all of the way after the first engine cycle?

Thanks!

[5FDP]

On the GEN 4 computers the regular TPS channel will only read to 88% for WOT and that is normal.

Perhaps you are logging the wrong channel or something is screwy with it. Remove it and re-add it to your channels display. The APP sensor will read all the way to 100% though.

[J-CUE]

I've remade my logging channels thinking the same thing but, it didn't change anything.
I'm logging; pedal, commanded, desired, and actual.
I'm also logging torque management requests, and the only thing that comes up is trans during a shift, and nothing else in between shifts.

As mentioned before, after a PCM flash, it will read 99% and open all of the way at wot but, after I shut the engine off, then restart it, it goes back to only reading 38% and not opening all of the way.
Also, when the throttle reads 99%, the MAP will read 99 and 100 KPA but, when the throttle reads 38%, the MAP only reads 95 to 96 KPA.


Is this because of traction control or RPM limit only allowing the throttle to open enough to support acceleration so it can react fast enough to limit?

[J-CUE]

And thanks for the reply, and trying to help me figure this out.
I appreciate any and all suggestions.

[GHuggins]

You said you modified the torque management on the transmission... You didn't zero it out did you? That will cause the throttle to cut like this... Since you haven't done that much - post the log and tune, but I'm willing to bet it's the torque management in the transmission...

[5FDP]

Didn't even think of that at first, the 6L80e can be very picky with TM.

I bet I removed no more than 10-15% at the most and my truck shifts exactly like I want it, nice clean and chrisp shifts. Enough to bark the 1-2 shift but still not so harsh that it slams gears and bucks.

[J-CUE]

Thanks for the replies.
I'll try to post the tune and a log soon, I've been busy with visiting family for the holidays.
Thanks.