When I am under load picking up speed between 1500-2000rpm, I hear this chatter noise. This is only in 3rd, 4th, and 5th gear. I'm thinking its because there isn't enough load in gears 1 and 2. I cant seem to figure out what it is. I'm guessing it's coming from the transmission? Is there any idea what could be causing the noise?

Here is a video describing what I am talking about. Notice the chatter between 1500-2000. Please ignore the thud at 8 seconds. I hit a bump. I believe the thud noise is due to bad pillow ball bushings.

 

Hard to tell from the video but it really is not good to lug the car like that because most tuners do not tune for it. You are putting the car in odd cells that generally do not see boost. Could be anything from the engine knocking to something rattling.

 

Found there were a couple of screws loose underneath the dashboard. Tightened it up and no more rattling!

 

Hmm..usually its a Loose nut behind the steering wheel..lol!
Screw loose you say..hmmm...(welcome to the club!)

 

good to hear you found the issue

My FD has never liked cruising below 2,000 rpm... it acts like I'm on and off the throttle repeatedly and I've wondered if others experience the same?

 

with the stock flywheel I could cruise in 4 or 5th smoothly from 1800rpm and up. With the act prolight flywheel I can't anymore and have to be closer to 2.5-3k.

 

yes and yes to both of those my car hates being under 2k rpm lol . it starts to lurch if I am to light on the throttle . if I am a bit heavier say -10 inches of mercury it wont lurch even at under 2k . but I don't make a habit of doing that.

 

^ thats reassuring, I've always had a light flywheel