limp home means just that. get it home, then fix it before driving again. When mine was in that mode, as soon as i hit the gas it would stall.... but in the cool note, it sounded like a SBC with a really lumpy cam.
The PCM rotates between cylinder groups firing some and not others. The ones that aren't firing, it allows the air that's being pumped through to cool the engine.
In theory, it works but several customers have just "roasted" the engines when trying to "limp" home.
The best bet unless the car's under warranty is to shut it down ASAP and get it towed.