Isn't "open loop" considered "limp" mode on our cars?
For instance, when your car has a sensor fail, the computer changes from closed loop function to open loop function but the car then runs off stored Keep Alive Memory (KAM).
Its what I was referring to when I went through all that O2 sensor stuff. Its just not called "limp home" like the 05's.
Its also not like many other cars (such as my Mercedes) who have "limp modes" all over the place, including the stability control system, the transmission, and of course the engine controls.
In the case of many of these systems, like the one I mentioned in my ML500, getting the tranny into Limp Mode means you are LITERALLY limping along in first gear until you get to a garage that can repair the car. Same thing with some cars and their emissions controls, they will shut down and allow the car to barely perform, almost undriveable, until the car is repaired.
The open loop backup (closed loop refers to the fact that the Mustang uses sensors within a "closed loop" to make ongoing changes within a certain set of limits to minimize pollutants, for instance, or maximize gas mileage, whatever the closed loop program is designed to accomplish) and its blah performance is the reason why we always recommend keeping the front sensors intact (and the closed loop process working) - the car just runs better with that way. But with our GTs, the car is not totally compromised in the open loop state, at least not as badly as some other vehicles. LOL, I've seen guys running that way for months, not that its a very bright thing to do.
With the 2005's and their "limp home" error message, I'm not sure how compromised the car becomes while it is "limping" around.
But OK, if we want to say that the open loop backup is a "limp mode", I could see that. Shoot, it might even be good psychology. Usually when I see this discussion, its because some member has slammed an offroad midpipe on his car, disconnected or thrown away all the O2s because some mastermind told him the only thing they did was turn on a CEL, and was now wondering why the car didn't seem to run properly.