Removing Noise from time across signal data
Is the width of your 5000-amplitude pulse always the same? If so, then just discard your signal samples that occur after seven seconds. If the width of your 5000-amplitude pulse varies then try lowpass filtering (experimenting with different lowpass filter bandwidths) your signal to see if the filtered signal contains the information you desire. If the width of your 5000-amplitude pulse varies then you might try differentiating your signal and measuring the time instant $t_o$ of the large negative amplitude transition. Then just discard your original signal samples that occur after $t_o$ seconds. Good Luck.