I travelled 2,000 miles roundtrip in my own vehicle to perform a wedding (as I am legally a minister and registered officiant), without charge. Can I deduct the mileage?

[hweins01]

I do not primarily work as, nor earn income from, being a minister. However, the main purpose of this trip was to perform the wedding.

[Mike9241]

then what you are doing would seem to fall under being a hobby and hobby losses/ expenses are not deductible 

[hweins01]

I would argue that doing religious services as a minister does not merely qualify as a “hobby”, even if it is done without charge. Does anybody know how tax law specifically applies to ministers and clergy in carrying out their duties?

[MaryK4]

To be a business deduction, it must be ordinary and necessary.  To be a business, there must be a profit motive (that is how the "hobby" income rules apply)- and not charging does not seem indicate conducting as a business.  

Because you would be taking the deduction against no business income for an endeavor that is not regular or recurring, you would have a loss that could be used to offset other income (from your job), nd the IRS would most likely not look favorably.  

Here’s what taxpayers need to know about paying taxes on their hobby activities

@hweins01