NSEU,
Check your tank vent, if its blocked you can get a vacuum in the tank that causes fuel starvation. Worse on longer journey's.
When you stop,air seeps in while your looking around and the car runs normal again untill a vacuum builds up again.
To test it, stop and take the fuel cap off asap and listen, i've come accross it a few times on different cars.Its a real pig to figure out the first time as it leaves no evidence.