My SVT was bucking when I let off or cruised around 2600-3000 rpm. It seemed fined at higher rpm like you describe. The problem turned out to be the fuel pump. They swapped it under warranty.
My $.02
Cheers
'99 Silver Frost SVT #2602/2760
K&N, Eibachs, 17's, DMD, OBX Shifter (my bad), A6 Sidemarkers, CTA Intake/Pipe
Some days you're the bug. Other days you're the windshield
| 
