The car runs great when the outside air temp. is cool. Now that summer has arrived, temps here are above 100. Starts and runs fine for about
30-40 miles depending on the temperature. All of a sudden the car lacks power when accelerating, the engine seems to surge while speeding up. Pull over and shut the the car off. I heard a low whistle sound coming from the fuel tank, it was the fuel tank vent hose. I opened the fuel cap and alot of air pressure escaped as well as being sprayed with fuel.Attempts to fix the problem are as follows: Checked all fuel lines for blockage including the return line from the fuel rail to the tank. No problems Replaced the fuel cap, no change. Replaced the fuel pump, no change. Replaced the fuel pressure regulator, no change. I am not sure what else to check. Please can someone help me with this problem. I drive this car 145 miles a day round trip to work. Only source of transportation. Thanks for any replies!