Why does the crank sensor keep going out on 2005 nissan altima?

Poor quality part is usually the problem ! Another mistake commonly made is not replacing the CAM-SHAFT position sensor at the same time CRANK-SHAFT position sensor replacement is needed. BOTH of sensors must be replaced at the same time - using identical brand of high quality parts!!

There is a recall on the crankshaft position sensor for your car; it's NHTSA Campaign # 07V52700. The recall mentions that the sensor "overheats" causing it to loose signal. According to the information on the NHTSA website, the remedy is for dealers to program the engine control module. I suggest first calling your local Nissan dealer to see if your car is covered under the recall. If it is not, I suggest contacting a professional repair facility, such as one listed here: https://repairpal.com/repair-shops, to diagnose your problem firsthand.