[mantra]

I encountered a new problem today while I was driving in the freeway, once I was getting to 70 mph my car starded shaking backward and forward like it was struggling to keep speeding, so I got out of the freeway and it ran fine at low mph. Ones again I tried getting on the freeway and it ran fine I got to 85 and so with no problem. so ny any chance do you guys know what might be happening to my car its 67 mustang coupe with a 289, automatic, Edelbrock Carburetor 4bbl. I appreciate your help thank you.

[jay67fast]

From your explanation, It would appear to POSSIBLY be the engine running/not running, as it would with:
A) bad gas
B) dirt in fuel line or carb
C) Fuel supply problem
D) Ignition problem
If the problem hasn't re-appeared, It would seem to me to be a bit of dirt in the fuel line or carb (since passed through). No action necessary.
If the problem re-appears and is intermittent or constant, then you'll have to start eliminating possible problems one by one. Let us know if you need to go farther with this.
jay67fast