I get this weird vibration when the engine hits 2000 RPM in any gear, its more noticeable in upper gears. It comes and goes very fast when you reach the 2K mark, it is very annoying.

I think its safe to say it is the engine and has nothing to do with drive train since it occurs at the same RPM regardless of gear. If you rev the engine to 2K in neutral the vibration can not really be felt. It appears the engine has to have a load. It is extremely noticeable in 6th when you cruise at 70MPH (2000 RPM) again, I tend to really feel it in the seat rather than in the steering wheel. You can also audibly hear it too.

I checked the exhaust and it appears to be tight and not rubbing the chassis.

Does anyone have any ideas why this happens? Could it have something to do with my headers and bullet muffler in place of the catalytic converter.
I really want to fix this.
Thanks.

 

I think it just has to do with the vibration at that RPM. It just happens to be more noticeable.

 

does it get worse at a higher RPM as well.... it will go and then come back.

It's most likely the driveshaft.

Bret

 

No it does not get worse at higher RPM's.
It only happens at precisely 2000 RPM in all gears.
It seems to be engine RPM dependant and not drivetrain RPM dependant.

 

Sounds like it's just the harmonics of the drivetrain. I know at certain RPM mine will also vibrate a little differently, more or less, than normal. I also noticed the specific RPM changed when I went to a poly trans mount. I don't think anything is wrong, but check all your mounts just to make sure.

 

One other possibilty here.
When I have the bullet muffler in place of the catalytic converter, there is no support mechanism in place that slides into that rectangular rubber mount that attaches to the tranny. This mount I am referring to is in place on my cat.

I wonder if the absence of this exhaust pipe support could be causing the problem, I mean were talking about 6 feet or so of floating exhaust pipe that might be vibrating. Maybe the support mechanism I am referring to is not really for support but rather there for vibe dampening.
What do you think?

 

Try disconnecting your driveshaft at the rear-end rotate it 180 degrees and bolt it back up. No cost to you and it might help, or so I've heard.

 

I don't use that exhaust hanger you're talking about and I have a cat there now. I do get some extra vibration in the 2k RPM range, but I doubt it's because of the exhaust hanging there. Mine wasn't even noticible until I installed the poly trans mount.

 

it might be a bent input shaft into the trany thats how mine acted when it get tweaked.