A couple weeks ago after a hard night of rain i started my truck and when i started to accelerate or just a steady speed the truck has a very bad misfire and some poping. I went to autozone when they open the truck was running a little better by then still misfire but havent heard it pop since the first time. When autozone scanned it the codes came back for the crankshaft sencor and a misfire on #3. I replaced the sensor and it ran good for about a week then again another night of hard rain and it happened again. Later that day it ran fine but I still decided to replace the plugs and i replaced them with oem plugs. It rained again that night and now its been dry for several days and the trucks still doing it. Ran the codes again. Came back with the same codes along with both banks running lean when I scanned with a better scanner. Any ideas or help as to where I should look next? 2003 4.2L V6

 

Apply waterproof dielectric grease to inside of crank sensor coupling and spark plug terminals and reconnect. High voltage and moisture doesn't mix well.