Lindsay Lohan has officially pulled out of her "20/20" interview with Barbara Walters ... and TMZ has learned it was all because her new PR team didn't want Babs to grill Lilo like a cheeseburger over the ongoing investigation in her car crash.
Lindsay was scheduled to sit down with Walters this week ... and we're told when she originally agreed to the interview, it was supposed to focus on her new movie, "Liz & Dick."
But sources close to the actress tell us ... in the past week, producers made it clear to Lohan that Barbara wanted to talk about her personal life as well ... including allegations that she lied to police about the June car crash on Pacific Coast Highway.
We're told Lindsay's new PR team, Rogers & Cowan, felt it would be a mistake to put Lindsay in the hot seat ... where she could possibly say something that could screw up her case ... so they pulled the plug.
Sources tell us Lindsay feels terrible for canceling on Barbara, especially since she considers Walters a family friend, and wants to reschedule as soon as her team feels the time is right.
10:31 AM PT -- An ABC News spokesperson tells TMZ ... "We are disappointed that Lindsay cancelled the interview and wish her well."