Just bought a 91 sentra "beater" commuter car for work. It has the 1.6L engine. Anyway, it needs work. It would chug along when you push the gas and shake & shutter - severe hesitation. Acceleration was almost non-existent. So I was able to putt putt it all the way home knowing I had to work on it. Today I replaced the fuel filter and fuel pressure regulator. It starts and runs smooth for about 3 seconds then dies. Now it won't even hold an idle!!!! But every time it starts right up nice for 3 seconds and dies. What gives? It's getting fuel. Fuel pump? Tomorrow I'm gonna check the dist. cap, etc. Any other clues as to why it won't stay running now? Thanx!!