What would make my car sputter, cough , miss what ever you want to call it went you floor it at 60 mph when it drops down into the lower gear, it does this briefly then takes off without a miss all the the way to redline.

 

dirty maf ?

 

dirty or malfunctioning throttle body. Assuming you have a stock throttle body.

 

could be a little misfire from a bad plug or coil

 

When you were at 60. Had you been cruising at 60 for a while or only a short time.
Stayin at highway/interstate speeds causes a bubble to form in the gas pump. And pushing like that sucks it in. Sputters then back to normal

 

I had been driving at low speeds and some extra idleing time, I took it back out and run the crap out of it and it seemed to quit. I see how it acts this week-end.

 

Looking at your mods, it could be any number of things. I'd check the spark plugs, how many miles on them?

High flow cats could have partially melted. It's not uncommon apparently.

 

Lem-06 is referring to the TSB for the fuel pump issue; I had it on the wife's '06 V6. Extended steady state cruising followed by hard acceleration and she'll buck, sputter, hesitate, etc..

 

All good suggestions as referenced above.
I would check the fuel filter as a precaution too.
Good luck.