Tranny Lags

If I drive my SLS normally it shifts through all gears just fine without any problems. I like to clean it out when I get on the highway and when the coast is clear usually bring it to 100 and then drive the speed limit. The last couple of times I did this it seamed that the engine accelerates but the tranny won't "catch or kick down" The engine can raise as much as 2500 to 3000 rpm before it starts to go. I have checked the codes and have found nothing. The shift solenoids where replaced last spring and I have not had any indication that anything else is wrong. Any ideas where I should start to look would be appreciated.