Hey Scotty, long time fan! I have a 2003 Nissan Altima with the 4 cylinder engine. She has 170,000 miles, and still runs like it only has 90,000 miles on the odometer. Sometimes when I cold start the car the noise is pretty aggressive. It runs just as fine as any normal start, but Is this anything to be concerned about?

live with it, those engines are weak and yours is nearing the end. Either that or do a full rebuild on the engine.