cars still loosing power starting around 3500rpm

[fordgasm]

This is a tough one but I would consider the following:

1) Fuel problem, fuel filters should be changed yearly. Maybe fuel pump problem or injector problem or regulator problem.

2) If it's not a fuel problem then possible electrical, sounds like you have replaced these items like coil, cap, wires, plugs, etc.

3) You mentioned a plugged cat which is also possible, they usually will get real hot if they are plugged, maybe check that. Might be a good time to get that off road H pipe you always wanted

That would be my approach to solving this one from what you have described.

Good Luck!