imo 2 bar down on fuel pressure will not cause det and lean running, it will cut and not fire.
i have first hand experience of fpr adjustments and afr change from just 4 weeks ago on my supra, i was only doing the tiniest change of fuel pressure 0.1 bar but saw a considerable change in afr, a 2 bar drop in fuel pressure would drop the afr so low it would be off the scale of my gauge and not fire and you would know about it.