Stock Fuel System questions/help

[Nukem1040]

What causes a 5.0 to lose power around 60mph but still idles and runs fine at low mph?
I live up in Northern NY where there is no dyno or Mustang shop. This is basically throwing at a dart board and I don't feel like investing hundreds and getting no where.
Fuel pump? Size? Make?
Fuel filter? Yes
Distributer contact inside?

I'll give it a shot to start somewhere.

 

[93Cobra#2771]

Losing power at WOT or cruise or?
Sputters, pops, or backfires or?
Check engine light on or off?
Modifications on car?
Recent changes or mods or has always had the issue?

 

[Nukem1040]

This car was gutted back in 2006 and I have been piecing it back together ever since. This was actually the FIRST time I have ever drove this car after owning for almost 10 years. So close, but so far away. We keep having crappy weather up here in Northern NY so it's making it hard to go pull the car out of storage.
I just ordered a new fuel filter and Fuel pump from LMR. Will start there.
Going to put Seafoam in the fuel tank and run a full tank of 93. I'll also run it through the intake and clean that out.

On to your questions:
The loss of power would happen at around 59-61mph while cruising. As if a loss of fuel i think.
No sputtering, popping, or backfire. Very nice idle and rumble sound.
I don't believe the check engine light was on. I'll recheck when I pull her out.
Only modification on the engine is believed to have a cam in it because the way it idles. BBK headers and exhaust. All stock.
Can't answer the last question because this is the farthest this car has gotten since being gutted.

I'll do as much as I can with "How to" forums but will have to ask questions. I've lost my touch with working on these over the years because all the moving and deployments and now I don't have any mustang shops near me.

 

[93Cobra#2771]

Hold off on the fuel pump install. Get a fp gauge on it and monitor fp during the event. If pressure is in spec you are good.

If you're just cruising and the event happens, it is a low load situation which doesn't point toward fueling issues.

Is it during steady throttle or initial tip in?

 

[Nukem1040]

Sorry for the late response. Getting home late this week.
I got the box in today. I'll wait as you recommended. I'll have to find a fuel pressure gauge to see what's going on.
Yes, I'll be on a straight away flat roads, steady throttle, and as soon as I hit about 59-61mphs, it feels as a loss of power, as in a smooth sputter, not rough. I didn't get on it, but I want to test getting on it over that MPH and see what happens.

What does that mean, low load situation?

Can't thank you enough for helping me on this.

 

[WillyB93]

Sorry for the late response. Getting home late this week.
I got the box in today. I'll wait as you recommended. I'll have to find a fuel pressure gauge to see what's going on.
Yes, I'll be on a straight away flat roads, steady throttle, and as soon as I hit about 59-61mphs, it feels as a loss of power, as in a smooth sputter, not rough. I didn't get on it, but I want to test getting on it over that MPH and see what happens.

What does that mean, low load situation?

Can't thank you enough for helping me on this.

You can generally rent the pressure testers from local parts stores, did you calibrate the throttle position sensor since the car has been back together? https://www.youtube.com/watch?v=HUwr0g5Qn7s

 

[Nukem1040]

WillyB, Gotcha. Thank you for the video as well. I remember doing that to one of my first 5.0's years ago. I have my homework set and will get on this. Might go get the car out of storage today. 30 degrees, but clear skies and dry roads.