****, just realized The tune is EFI live. I have hpt, may still have efi software to view it though.

 

i didn't read your entire thread, but I had the same issue when I put my 427 in for some reason. anything over 12 psi put it in REP. even tho the exact same setup had no issue with 20 psi on my 6.0.... I changed out every part, TB, TB harness, Tons of sensors.... i gave up and did a nelson stand alone harness with 02 camaro pcm and cable TB, have never had an issue since. This is the only thing that fixed mine. good luck

 

I know this sounds like a shot in the dark, but can you log battery voltage during the run? If the alternator is dropping out at higher revs the throttle motor will lose torque momentarily too. Between that, the blade spring and the vacuum it could theoretically be a problem.

I also found this on LS1TECH. Not sure that it applies to your exact problem though:
" Go to engine diagnostic and multiply the 1514 table 200%."

 

Have you checked to see if your Desired throttle Area Normal table has been altered at some point?

 

I have been in contact with several very experienced tuners, and they state that a P2101 can not be tuned out. All of the tables associated with the ETC have been increased properly. I will check a battery voltage log later today to see what that shows. I truly feel it is a design flaw with the TB. The blade is offset in the hole letting more air enter one side. Well the more air is moving faster and causing a vacuum like an airplane wing. I am going to order an LS2 TB and see if the offset in the other direction will help keep it opened. If that doesn't work I might weld in dividers so the blade will line up and cut the air without putting stress on the blade. I can't find the proper magnets to upgrade the motor. I might look into a cable swap. I'm sure that would correct it. I don't plan on spending too much time on it this year, I really want to get my Chevelle done. If I can't get it fixed easily, I am just going to swap to a turbo.

 

not what i wanted to here but whats the worse that could happen? you go turbo on your truck and the chevelle gets done.

 

turbo sounds like a great idea.

 

Post up your tune and a coresponding log if you dont mind

 

 

Here is a log and a tune. I went WOT at frame 1219, and you can see the throttle blade fluttering. At frame 1229 you can see it start to drop off, and then it goes into REP. Sorry to take so long in posting this.