The reason behind the dropping of the fuel pressure is the weak pumps, so it is very important to take good care of the pump of your tester. Also, it can be due to the restricted lines, dirty filters and improper tank venting so it is important to check if the pump is in good condition or not. You can easily inspect that your fuel pump is properly working or not as it makes a sound when not in good condition. Also, it can indicate to you by sputtering or coughing that it is not in a good working scenario and there is some problem with it.