INDIANAPOLIS -- Frustration is mounting at the Indianapolis Motor Speedway.

Drivers and fans will have to wait another week for qualifying.

Rain, which has cut short or canceled every practice session since the track opened for Indy 500 practice last Tuesday, held off just long enough Sunday to give everyone a little taste of what they're missing.

Defending Indy champion Dan Wheldon and Sam Hornish Jr. both managed to post speeds above 228 mph -- the fastest so far this month -- during a brief practice session that was supposed to be only a warmup for the start of qualifications for the May 28 race.

Two-time Indy winner Helio Castroneves, Hornish's teammate, and Scott Dixon, Wheldon's teammate, added laps over 227 as 24 drivers took advantage of the short dry spell and nearly perfect track conditions -- overcast skies, no wind and temperatures in the low 50s -- to get in some practice laps in anticipation of qualifying.

But then the rain returned, wiping out time trials for the second straight day and prompting track officials to reschedule qualifying to next Saturday and Sunday, which were supposed to be the last of four days of time trials.