When I pull out in first gear and ease up on the clutch the car accelerates fine but as I move up on the clutch toward the end of pedal movement the car shudders and then gets smooth again when the clutch is fully engaged. If I try to start in 2nd gear the problem is even more visable. I also hear a lot of chatter once the gear is engaged (for the first 1000rpm). Any idea on what the problem could be?

I have a powertrain+ warranty, would this cover this problem?