High-speed photometric observations were performed of the Ap stars HD62140 (49 Cam), HD81009, and HD22374 for more than 60 hr in Oct. and Dec. 1986. Photometric measurements in the B band were reduced and the residuals obtained were subjected to a harmonic analysis, searching for periodicities in the range of a few minutes to 2 hr. There is evidence that the star 49 Cam is oscillating; HD81009 and HD22374 were observed in order to confirm traces of oscillation present in earlier observations, however, these possible oscillations did not repeat in the new data.