This is an odd problem and I can't seem to figure out. It usually occurs while cruising above 45 mph. The engine seems to just cut off...here's the odd thing if I let off or accelerate it clears up and seems to do ok for a while. Increasing the speed to 70 and above the issue becomes more pronounced to the point the car will shut off requiring me to pull off and wait a minute or two before it will restart. During the stumbles the fuel pressure does not fluctuate. I swapped the hep with another used one and have the same issue. I've cleaned and tightened all grounds and checked the harness connections and haven't found anything. This is a 2.5 with bb flashable sbec. The car runs really good outside of this issue any advice or things I should take a look at would be greatly appreciated. Thanks.