While driving down the road it starts to sputter at around 50 mph. when you step on the gas it stops. It gets worst with the a/c running

How many miles are on the vehicle? Have you every changed the fuel filter? Ford recommends replacing fuel filters every 30,000 miles.

If your Check Engine Light is on, have you checked for codes? The DPFE Sensor may be bad. When were the spark plugs last changed? Did you install the exact Motorcraft plugs that originally came in the vehicle? If they haven't been changed, I would replace them if you have more than 50,000 miles on them.

If the problem persists, I would add a bottle of fuel injector cleaner (e.g. Chevron Techron or Shell Regane) to the gas tank. I would also change the air filter and focus on the MAF Sensor--it may need cleaning or replacing. Ensure there are no air/moisture leaks by snugging up all mounting bolts.