It shouldn't drop that fast. It could be a bad check valve in the pump itself. You would have to check that. However, the black smoke tells me it is running rich at first. That leads me to believe you may have a leaky injector. What you need to do is turn the key to the run position to build pressure. Then, pinch the rubber fuel line from the fuel tank. If the pressure still drops, you have an injector or pressure regulator leaking down. If it doesn't drop, chances are it is the check valve in the fuel pump or a leak somewhere in the line.
Let me know what you find.
Monday, September 27th, 2010 AT 10:20 PM