Am going nuts with this one, I replaced the O2 sensors and and the spark plugs at 120,000 approx. I started to constantly get a fault code 1125, so i replaced the throttle body at the same time I would get an intermittent fuel starvation problem. I drive 42 miles each way to work, no problems in the morning but in roughly the same place 30 miles the fuel pressure drops from 380 (Loop 1 and 2 closed) to as low as 120, for no reason (cruising at 75), if i back off the throttle completely the system opens up and the fuel pressure jumps to around 440 and all is good, all the way home. Any ideas?

 

Abritinga I hope thats Kilograms per square inch cause in inch pounds it should be 50-54 Lbs, Any way might be fuel filter or fuel pump driver module. Unfortunately it can only be tested with high price scanners, can't see on line where to get one. The filter is easy it's in-line and about $10.00-15.00. It's the intermittent part that is not adding up. I don't think the computer controls the pressure just monitors it per say, maybe one of the techs on line can give a in depth evaluation. I'll keep searching if I find anything I'll pm the forum.
Did you connect the scanner on a ride-along to monitor the pressure or go by the code symptom

 

My Actron scanner is in kPa as per the TSB "The fuel line pressure should be between 320 kPa and 380 kPa"

I will drive home tonight and it will behave but tomorrow another story. Tends to happen more if I drive the car at times during the day. A temp problem/ as in residual heat in the engine bay?

Twice I have had to replace the battery because it just cooked under the hood and this battery now is a used on. Am thinking the problems started around then. Could it be as the battery heats up it changes the voltage to the ECM that in turn causes the problem?