If you have HP Tuners it would be a bonus but not necessary. At the strip the other day I made 8 passes, during every pass the car has a slight hesitation/flat spot at 5500 -5600 rpms in second gear and in third gear.

The engine side is fine, AFR is at commanded, spark good, the rpm's do recover and the 2-3 shifts at 6400 so the engine is fine. I have very good 1/8 mph (97) speed just trying to figure out the flat spot.

You can't see the issue in third in the pic because of the long arc but it there.

 

is the converter locking? monitor tccmode

 

I will check tonight. I have the tune setup so there is no TCC apply except in fourth gear but I will monitor is anyways to see if something freaky is going on.

 

I logged some data last night and found what is happening.

The torque converter is functioning properly. It has a flare at that RPM range that is causing the issue. I did some research and made some changes with HP Tuners to see if I can clean that up. The log showed the trans pressure to be lower in second gear than in 1 and 3 and a table in HP Tuners matched the difference in readings. I adjusted the pressure and tweaked the force motor table.
I will try to drive again tonight and see what happens.

 

hmmm...that sounds like low fluid

 

No, its not low fluid.

Here is a follow up log and more new info.

http://www.hptuners.com/forum/showthread.php?t=25993

If you know what TCC Apply Enabled means, let me know.