I have a 1996 Mustang GT, 4.6L Automatic Transmission, when I drive long distances, I drove 78 miles today and out of nowhere the car is running very loud and lower than usual & starts slowing down fast. No matter how much gas I give it, it struggles to go over 40mph and does not respond to the gas pedal, and under 20mph it tries to shut off. I had to keep it in neutral at stops just to keep it running and it had real trouble accelerating from a full stop. Oil is barely over normal, as is the coolant. It has no cats on it. It doesn't seem to go over 2,000 RPMs. This has happened 2 other times, both times only after driving it a ton with little to no breaks. I work roadside so I am constantly driving. It only happens when it's hot. My husband is a car guy but doesn't want to find a solution other than selling it, I LOVE my car, I want to keep her forever, please help! The photo is when I was on the freeway earlier, and flooring it to show that there was no response to the gas I was giving it.
generally either fuel pump is wearing out or cat is clogging up. Both can be pressure tested