Blunder on
Definition 1 of 2
Pro Tip 1/3Muddled Persistence
Used when someone keeps going despite confusion or lack of direction. 
Lost in the city, she blundered on, hoping to find her way.
Pro Tip 2/3Not Negative
Though it implies clumsiness, it can also show determination. 
He blundered on through the complex puzzle, not giving up.
Pro Tip 3/3Casual Tone
Best suited for informal situations or creative storytelling. 
The toddler blundered on with the building blocks, undeterred.