What Exactly is Limp Mode?, Can anyone explain this? Options

[Lil-Joe101]

So I'm wandering if my car is in limp mode. Why? Well the check engine light is on and she idles fine for a minute or two, then completely drops fuel pressure and dies. If this is not limp mode then what is causing this? I just replaced all for injectors, believing that this was the original cause for it not running right i.e. rough idle, fluctuating fuel pressure before it completely drops and dies. I've also done the general maintenance as well like change oil, flush and change both radiator and heat exchanger, replace h spark plugs and also the battery. I have replaced the fuel pump, filter, and now injectors. She idles fine now, like a dream then given a minute or two drops pressure and dies. Also she's running really rich, so much in fact, you can smell the extra fuel that's being dumped to compensate. Can anyone tell me what's going on, or what it is I'm doing wrong here, cause I'm lost, frustrated beyond belief, and almost fed up with the whole thing.