Since it acts up in turns I would do some yanking and jerking on the wiring harnesses.

changed fuel filter. engine still dies. cut open old one and it looked brand new. Fuel pressure KOEO 45 psi, engine running 54 psi
It now has stopped dying as much. but it still does it.
old codes are gone. I didn't clear them, they just went away.
These new ones showed up.
codes U1301 class 2 shorted to battery.
U1064 lost comm. with BCM.
U1026 loss of class 2 comm. with ATC.
I then wiggled and moved wires all over the place (under dash and hood) with engine running and no change.
took out combs and checked 2 splice packs with class 2 data lines in them. one of them is all grounds except for 1 data line and it was ok. checked for short to batt. on other one and found none. checked for short to ground and found none except for 1 pin that is a ground and it was ok. All class 2 voltages read about .4mv.
so I hooked up scan tool again and now all codes were gone!!
But listen to this, I found something odd. on scan tool at WOT, the throttle position desired and indicated angle both only went up to 30% ! This would also explain something that happened last year, I was checking something and wanted to crank but not start engine. I held pedal to the floor and turned key and about blew the damn thing up because it started at WOT.
And the TPS'* have bad readings. 1 goes from about 4.2 down to 3.5 and other goes from .88 up to only 1.7.
they are both 5v circuits, one is supposed to go from .5v up to 4.5v and the other goes from 4.5v down to .5v (I put this in for others reading it, I know you guys already know that) They aren't even going to half range. yet no codes are being set for them.
Bad throttle position sensor???
Let me know what you think. and thanks for the help!

I would check to see if the TPS follows your foot accurately throughout its travel, and doesn't bump or jerk around along the way.

thanks, I'll check it out.

took it off and put on my bench. checked resistance, both sensors read smoothly throughout their range.
sensor 1, 1.09k ohms to 4.1k ohms.
sensor 2, 3.6k ohms to .6k ohms.
I'm going to put 5v to it in the next few days and read the voltage when I move the pedal.
Does anyone know where I can find a cliff to drive this off of? LOL.
I'm gonna keep at it.
the thing I don't understand are the weird codes I'm getting, and so many of them. Some may be from having the data lines disconnected with key on. But there were others before. Driving me crazy!
Until next time, Thanks for your help!

hooked up fuel pressure gauge again.
KOEO read 40psi
engine running 45psi
FSM says 45-55 engine running.
so I guess after all this, I have another bad fuel pump. I already ordered one. A GM Genuine fuel pump. both the replacement pumps from RockAuto were their brand, Ultra Power. they are junk!!!

I would dead head the pump and see what you get. Maybe the regulator.

Has a new regulator on it.
dead head means no return line right? do I just disconnect it?

It'* just unregulated pressure test with no return.
Ho much does the pressure go to with a snap throttle?

will test snap throttle pressure. but I did a load test by brake torquing it and the gauge didn't move. stayed at 45psi.