My Disco 2 is stalling at redlights at random times and also giving jolts while at speeds of 20-55 miles per hour only for a second. I've cleaned out my upper air intake system as well as giving the idle air valve a flush this morning but the engine will still cut out in reverse or coasting in drive. It's not throwing any codes and I did fuel treatment as well as refilling the tank so I don't think I have a fuel delivery system problem, any ideas or tips?