I have a 99 Eclipse non-turbo 2.0 manual trans-axle. Car's been great, never any major problems. How ever for a little while now it's rattled when I take off from stop. It doesn't always happen, really depends on how i take off. If i hit a really good clutch/gas combo it takes off smooth as glass, but some times if i hit it hard it will have a thunk thunk thunk as the clutch grips. I also have the same sound when i go over a sizable bump. not all bumps cause it, larger repetitive bumps do it more than smaller ones, but sometimes one large one won't do it either, again kinda depends.

I thought it could be my engine mount, but i've ran some recommended tests and it seems solid.

I thought it could also be my ball joints, but those were replaced back in 04 or 05 when the recall was out.

Any thoughts? Thanks in advance.