Okay Guys, Im at my wits end and I know if anyone can help its the people here. So this is the deal. I have a 2004 5.6 liter that has been acting up. when I am accelerating at around 2500 rpm and greater the battery light flickers and the engine becomes sluggish and then it will come back to life. I have replaced the alternator twice, new plugs ,coils, fuel filter, air filter, fuel pump control module. serpentine belt and battery. Now this truck has 76k miles and it was in need of a tune up anyways. The problem is still present. I went in the DTM and observed the voltages when it happens and it drops to almost 12 v and then slowly comes back up. This only happens when there is a load on the truck. I notice the security light starts blinking and when this happens and if I take it out of over drive it will reengage it. It seems like the computer is resetting. I am lost at this point and could use any of your wisdom.

I do have the cam phaser problem on this truck,
Thanks

 

For a truck with that low of mileage I can't imagine there being any mechanical issues. There are so many sensors for the computer to set fuel levels you'll be spending money changing parts forever. This is one time where I would suggest taking it to a shop for testing. All that said, it sound like a vacuum leak to me, not electrical. The flashing security light is just an indication of the problem.

 

thanks Marc, I think you have the right answer there. I appreciate it.

 

Have you checked your fuel pump drive module?

 

Moved to 04'-08' section.