After driving 2002 suburban for 1 hour or so, start to have problem with engine stalling out when you excellerate into the overdrive. Once you pull off the road and wait a few seconds it will start right back up. Can not get this to happen at the dealership. Have changed the fuel filter but still having the same problem. Have a fuel pressure gage on it now with long hose so I can see it on the dash, but have not been able to get it to stall out again. Pressure is at 50 at start up then drops to 40 while driving down the road and drops to the 30 is when you tromp on the gas. Any suggestions on what to try next?