Typo: its an 87, not an 89. So I filled up the left (driver side) gas tank after I had been using the right tank, though not to empty. After I had filled up, I started the truck then switched to the left tank. Thats when the truck shut itself off. The fuel gauge shows a full tank, but it wont start on that tank. Could it be the sending unit? Or did I screw up the Fuel Injection by switching tanks while the engine was running? I have a feeling I wasted $60 filling up a tank I may have empty soon.... Also, the left tank was not empty prior to filling it up. The original owner told me he had just replaced the fuel pumps on both tanks. He's a mechanic himself, so I trust he would have tested them, making sure they worked.