ESP Malfunction?? - Help!!!

In fact, I am struggling to get my rpm's above 4000 and it takes FOREVER to accelerate! If I switch to "M" and manually control the gears, I can get "normal" response from her, but outside of that, it ain't happenin! I can't even manually turn off the ESP now (there's no light on my dash at all to reflect the ESP is off). Has anyone had this happen to them? Will an ECU reset help? (I have a Kleemann tune though, so I didn't really want to do this if it's going to erase my ECU programming.) Does anyone have any answers/ideas? I would really appreciate any insight anyone has. I will probably call my dealer tomorrow to take her in for service sometime this week (if they can get me in), but I'd really like to know what's going on... Bottom line, I just want my beast to perform like she used to!

Thanks, in advance!
. Oh well, I'm ready for 'em now!! 
Thanks, everyone for all of your advice!



