93 s4 with a hickup at 6000 rpm

[Bing]

I was cruising along at 75mph in 5th gear when a little civic ricer
with a park bench style wing and a coffee can style muffler  comes
rolling up along side.With 3 lanes of no traffic ahead i decide to
downshift to 4th and hit the WOT switch and  leave him behind .As i'm
setting up for a shift to 5th at 6000 rpm i get a misfire
(sput,hickup)sensation and the car slowed as if it slipped out
gear.But thats not the case because i had a hand on the stick and a
foot on the gas,tach drop of about 1500 rpm and of course a loss of
speed ,so i shift to 5th acceleration is on again like nothing
happened.no sputs burps or what have you....it has happened before on
a long 4th or 5th acceleration around 6000 rpm....any ideas of what to
check ????????
-- 
Bing
'01 A4 2.8QM 30v...
'93 urS4