My Blazer just hit its 150,000 mile mark. I want to see if I can keep it running strong at 300,000 miles. So my question is, what's the highest mileage you've heard of someone putting on their gasoline powered vehicle? My former boss took his Ford 150 up to 400,000 miles just by keeping up on maintenance and repairs before he traded it in. His current one is at 180,000 miles last I heard.