My car struggled to start sometimes so I thought it was time to get a new one.
No yeah. That's a good idea. It's nice to have a reliable vehicle.
No yeah is a confusing response people may utter in spoken conversation that means "yes." People often use it when replying to a statement or question to communicate that they agree with a person's decision not to do something, change something, etc.
For example, your co-worker may tell you, "I didn't think the spacing was right on the design, so I updated it," to which you reply, "No yeah. The new version looks good." In this case, the "no" part refers to the design's spacing not being correct, and the "yeah" part refers to the overall agreement in their decision to update it.
Another example is when a friend asks you, "Do you think I should have broken up with him after he said that?" and your reply with, "No yeah. What he did was wrong." In this context, the "no" refers to the boyfriend's indefensible words, and the "yeah" part is an overall agreement with her decision to break up with him.
The phrase is common in America, including California and Midwest states. You may also encounter it in other English-speaking countries, like Australia and New Zealand. People who use "no yeah" may also use "yeah no," which has the opposite meaning ("no").