Tax Write Off for Delivery Service

Hello, I first wanted to say thank you all for doing this! Here’s my question:

 

I work for Walmart Spark, Door Dash, and other delivery services which is self employment. I change the oil in my truck, wash my truck at home, and do any other routine maintenance work needed on my truck in result of all the miles I put on my truck working. I was curious if I can still write that off as far as my time doing those jobs and a labor rate lower than the body shops to put a value on what I’ve done? I’ve been writing my own receipts every time I do an oil change, truck wash, etc and taking a photo for proof. The way I see it is if I paid someone to change my oil I could absolutely write that off. But I don’t pay anyone to change my oil because I know how to do it myself and can do it for cheaper. So I feel like I should be allowed to write that off. Just wanted to ask that and see if there’s anyway you all could help me out! Thank you in advance.