It is not sinful, but you wont get them.
"Be it unto you according to your faith."
As your declared faith is that God won't give what you ask, then I am sure that's what you'll get from him.
ie. If you believe for nothing, you'll get nothing.
Personally, I have asked a lot of the Lord over the last 50 years, and as such I have received a whole lot.
For many decades I ran my own manufacturing business as an exercise in faith, and saw far more of God's intervention there than I ever did in church.
As an example, very recently my wife and I sought the Lord about moving house from the town we lived in. As we prayed, the Lord revealed that we should move over 300 miles away to a completely new area.
We visited that area on a number of occasions as we tried to tighten our focus on the exact location he wanted us to settle in.
Finally we decided to sell up and rent in that area till we found the right house.
We had the property agent in to value our house, and having agreed on the price he said he would send us the contract to sign within a few days.
The agent left us, and I followed him out the front door to do something. As I did so, a total stranger engaged me in conversation, and I happened to mention that I was moving house shortly.
He then immediately asked me how much I was selling it for, and without hesitating said he would buy it and he already had the funds in the bank.
So, after obeying the Lord to put the house on the market, it took all of 5 minutes to sell it to a completely passing stranger. Needless to say the agent was a little upset to lose his commission!
After renting for a while in the new area, the Lord led us to our new house with great clarity. Its a wonderful old Victorian house in a lovely remote village with five big bedrooms, bigger and better than anything we have ever had before.
Being retired now it was completely above our price range, but the Lord showed us how to buy it, and it is completely debt free.