1995 Mustang GT:

while driving at steady speed applying light light throttle to maintain speed car will start to chug and miss....if you let it miss and stumble long enough the engine light comes on. If you hit the gas it instantly works fine and if you down gear and let'er go for a gear the engine light will go off.

Car starts and idles perfect.
Car has tons of power
car accelerates perfect smooth while gaining speed.
NO recent mods or work done to the car, Just randomly started 2 days ago. And it doesnt even do it evertime your in the scenario of maintaining speed. it was fine all day yesturday

Only does this when your driving as if your stuck behind someone doing the speed limit and cant pass.

Car has had all the recent tune up things done and also had a recent MAF clean.

What would be your guess as what to look at?

Does the computer store a code for that engine light even after the lights off?

any insight would be great.
Thanks
Josh