So, I have another idea of what might be causing my pulsing / hesitation. The theory is I have a vacuum leak. The leak is in the line going to the fuel pressure regulator. The steel nipple on the intake manifold is VERY rusted. I wouldn't be surprised at all if it was leaking, though I haven't tested it yet. This could make sense why I get a surging effect while accelerating. The leak causes more fuel pressure, which the ECU sees via the O2 sensor and compensates, which effects vacuum, which causes less fuel pressure, which the ECU sees, and compensates, rinse & repeat. This is normal, but with the leak, the ECU can't compensate correctly?
The question is, how to fix it? Ideas welcome!
