My f150 300 died on me so I went and got me a "new" work truck. I now have a spanking brand new 1996 F250 with 5.8. It has dual tanks and now it sputters with the rear tank when under a heavy demand. The front tank makes the truck run fine. Also when drive under the front tank, fuel siphons to the rear. When I drive on the rear tank, fuel stays in each tank. While I'm asking questions, I have one more. My truck has a transmission cooler im pretty certain. I also have two coolant lines that go through a fitting thats between the oil pan and the oil filter. Is this a oil cooler or warmer? Thanks in advance.

 

sounds like a bad fuel delivery module on the back tank to me.