Sprint Cup driver AJ Allemdinger, who is on temporary suspension for failing a substance abuse test, said Wednesday through a representative that he has been told the test was positive for stimulant use. In addition, Allmendinger was said to be gathering all medications and supplements he typically takes to determine what produced the positive result. Allmendinger, 30, was suspended Saturday, just hours before the Coke Zero 400 at Daytona International Speedway, when NASCAR officials told him he had failed a drug test taken one week earlier after the race at Kentucky Speedway. NASCAR will not disclose the substance that Allmendinger tested positive for, as per policy that the sanctioning body has followed since implementing a new drug testing policy in 2008. In a statement released Wednesday by Allmendinger's business manager, Tara Ragan, the driver is dumbfounded by the positive result and was taking all steps necessary to isolate the cause. ''AJ tested positive for a stimulant. He has no idea why the first test was positive, and he has never knowingly taken any prohibited substance,'' Ragan said. ''AJ is collecting his medicines and supplements for testing to determine whether an over-the-counter product caused his positive test.'' Allmendinger is awaiting results of testing on a second sample that was sent to another testing facility, as per NASCAR's drug testing policy. He is the second Sprint Cup driver and third driver overall across NASCAR's three major professional series to have been suspended for a failed test. The results on the second sample could come as early as Thursday, but Allmendinger has already been ruled out of returning to race this Sunday in New Hampshire, even if the test result is negative. Penske Racing teammate Sam Hornish Jr. will fill in for Allmendinger in New Hampshire, as he did this past Saturday at Daytona. ''AJ and all of us at Walldinger Racing (Allmendinger's own racing company) respect NASCAR's testing program, and he has requested that his ''B'' sample be tested as part of the process of getting to the bottom of this,'' Ragan said. ''We will have the opportunity to review all of the scientific data surrounding the test following the ''B'' sample test, but our understanding is that AJ's test was slightly above the threshold.'' If the second test proves negative, or if testers can zero in on what caused the original positive test after reviewing the medications and supplements Allmendinger provides, it would go a long way towards his reinstatement. However, if the second test also comes back positive, Allmendinger will remain suspended until he completes a NASCAR-approved treatment program.