TMZ spoke with Randy's brother, Lanny Poffo, who tells us the wrestling legend suffered a heart attack while he was behind the wheel around 10 AM ... and lost control of his vehicle.
Earlier this month, Savage celebrated his 1-year anniversary with his new wife Lynn.
Savage was 58.
Macho Man began wrestling in the WWF in 1985 and became a superstar with his trademark catchphrase "Ooooooh Yeaahhhhh." "Macho Man" began his pro wrestling career in 1973, and joined the WWF in 1985, where he quickly rose to superstar status. He was a seven-time world champion during his nine year tenure with the WWF. In 1994, he left for WCW, where he wrestled 1999. After a short stint with Total Nonstop Action Wrestling, Savage retired in 2005.