My direction/thought on the O2 is because you are talking about it being warmed up and then having a problem. As pointed out, the O2 does not come into play until you are in closed loop. Therefore, if there was a "problem" in that part of the "information stream", it would not appear until you are warmed up.

As with some breakdowns in wires, it may be heat sensitive, in that, once the car warms up, it generates the break. This also brings up the thought of the wires that go through the harness around the egr. Heat sensitive.

You say its spark that is lost, so maybe the direction is looking at those egr wires and the cam sensor/crank sensor "conversation" (as in their conversation with each other and possibility of one of them being bad). Also, since it is definitely spark, that same wire loom that runs around the egr contains wires for the coil etc. Maybe next time it happens, you do a shake and bake on that loom and see if you can get spark back (if you want to do some checking in this area, Terry does a pretty good job directing in the beginning of this long ass thread; http://forums.2gnt.com/dcboard.php?az=show_topic&forum=5&topic_id=131904&mesg_id=131904&page=&topic_page=1 )

Keep in mind that this is all after my high percentage that it may be the ECU. You're kinda looking for "alternative" reasons for this to happen (plus it leaves me an out should it not be the ECU lol )

Captain Caveman

96 RS Turbo 11.414 @ 119.62 MSNS, Crower 2 NA cams, BW366, 10.5 comp, UDP, 60mm TB, W/A intercooler, 3.55 tranny 567.9whp 430tq
97 RS NA 13.188 @ 103.87 MSnS powered 12.5 comp, Crower 3's and 219.4whp with 175tq
98 RS DD 12.5 comp on stock ECU, LTH, Crower 2's, Koni, GC, Hypercoil, DG hats
99 OZ 5sp Stocker 15.856 @ 85.97
99 GS stocker auto 17.7@77mph!

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