So I think I got my other problem fixed. I replaced the original fuel pump because of my truck's start-then-die behavior, but the replacement pump(s) were cheap and I think they didn't work well. Here is the problem: 1997 Ford Ranger 2.3L engine, manual transmission If you turn the key on to start the truck, after it has been sitting for more than a very short length of time, it will initially start, rev up a bit, then die. After that, if you try to restart, it will start right up and run fine. If you turn the key to "ON" for a couple of seconds and wait, then start the truck, it starts and runs without dying. Sounds like a fuel pump losing pressure, right? Here are the things I've replaced that have had no effect on this behavior: Fuel pump x 3 Fuel filter x 2 Fuel injectors Fuel pressure regulator IACV With a pressure gauge on the fuel rail, no loss in fuel pressure is seen during the start-then-die event. In fact, the fuel pressure seems to increase as the engine dies (vacuum operated pressure regulator). My guess is that there is maybe a tiny leak somewhere in the system and that causes the fuel pressure in the system to leak out -- and air to leak in (?). Then, the injectors get hit with a little bubble of air that makes the car die. I guess the thing to do would be to get a UV dye for the fuel system and see if that will show any leaks.