99 f-250 4x4 7.3

[snowlover]

I hav 99 f-250 with 159,000 miles, its my work truck, and everytime when it rains it skips, only when it rains!! or the road is damp!!, it keeps coming up a cam sensor code, i had my local shop replace about 4 cam sensors since spring time.
I took it to my local ford dealer, they replace the cam sensor harness, and then this afternoon driving in the thunder storm same problem.
I do hav a crack windshield on the passenger side, if don't kno if water is getting in somewhere, or could it be the IDM box, that was replaced about 4 years ago, but it was a rebuild one. Looking for some help and ideas