2002 suburban 8.1 4l85e slipping or shuddering?

[lumpy85]

I bought a 2002 suburban 2500 with the 8.1 and the 4l85e 2 months ago. The truck is 4 wheel drive and has 80,000 miles on it. The previous owner had the transmission fluid changed at 35000 miles and im going to change it this week, but ive noticed a couple times when im on the gas pretty good, like getting on the highway the suburban will almost act like its cutting out or the transmission is slipping. It shudders like its not getting fuel, or something. I replaced the air filter, fuel filter, and changed the oil so far.

 

 

 

Anything i should look at next? the transmission fluid isnt the cleanest but its not burnt yet.

 

 

 

Thanks for the advice in advance.

[ATMINF]

The 8.1 were known to have issues with their TPS(throttle position sensor) I think they even had a service bulletin on it.