accelleration varies; transmission or turbo?
 

Am not a seasoned Audi owner; had my 2001 A4 Quattro 1.5 years and
turbo replaced at 40k miles due to oil sludge failure. Like new
turbo's performance but feel somehow that accelleration is variable
when punched from start or low speeds. Good when I get aggressive
response; not so good other times. Seems consistent when switched to
Tiptronic, however. Possible cause?