4 months ago we purchased have a 2001 Grand Prix 3.1, 70,000 miles. The lower intake gasket were replaced because of a minimual leak (not noticeable on the ground). Shortly after that it started making a fast ticking noise. Sounds like a clock ticking loudly. Pretty sure it's coming from the top of the engine. Loud at start up until it's warmed up. Then it get somewhat softer. It's off and on while driving, but not as noticeable. It's not leaking any fluids. It drives fine...good power. We took it into a repair shop...they listened to it and said we needed a new engine $2200 repair. I'm having a hard time grasping this. Is there anything else it could be?