I have a 1996 Civic Lx (Auto) and it's making this weird clacking noise and a squealing noise, also it has been getting about 19mpg city and 23mpg highway with an idle of around 600rpms. It was sitting out for about 4 years until I wanted it.

The squealing happens most frequently as it starts about 10 seconds after i start the car up and only happens at idle. Its high pitched but too low pitched to be an accessory belt. The pitch also pulses very quickly and can't be heard much from the interior but can be heard outside the car.

The low idle seems to happen as the car heats up. The idle use to dip like it was the IACV but began to level out. Now when the car is turned on it goes up to 1,500rpms and slowly goes back down to around 600rpms as the engine heats up, with the whole car vibrating.

The clacking noise happens the least frequent. Although, it has been happening more frequently than when it started. It used to happen when I'd drive 25+ miles on the highway. Now it happens at random when i drive 3+ miles. It gets worse the more i drive with it making the noise and the noise will fade away at around 2,800rpms in 3rd gear and will not stop in 2nd and 1st. Power is significantly deceased, as at idle the car struggles to move itself and the throttle feels less responsive.

Videos of clacking noise

http://tinyurl.com/lq6hv98 - Trying to figure out where it's coming from.
▲ I drove 20 miles. ▼
http://tinyurl.com/mt7pjgx - How the noise sounds when revving it.

http://tinyurl.com/k2fyspr - Astonished at how far I drove for it to happen.
▲ I drove 3 miles.

What Has Been Done to the car in the past 4,000 miles that might be significant.

-New Exhaust
-Used Transmission from wrecked 2000 Civic DX with 70,000 miles on it.
-Tune Up Kit -All new accessory belts
-All new brakes
-New gas tank and repaired gas lines

I have asked 3 people. 2 from AutoZone who couldn't give any advice except keep an eye on your oil levels. Another person who i know is experienced says it sounds like its a valve. No codes are coming up on the OBD-II scan.

I just want to get more views on it as i still am not sure what is causing this.

-UPDATE- 3/20/2015 6pm

YouTube links:
(phone was having troubles uploading it, but now I'm on my pc)

- Trying to figure out where it's coming from.

- How the noise sounds when revving it

- Astonished at how far I drove for it to happen.

 

Sorry, but I don't feel like signing up for a dropbox account. Can you host it elsewhere?

 

Sounds like the belt tensioner needs adjusting.
Did you check that?

 

As mentioned, if you want feedback, host the videos on YouTube and paste the shared links.

 

Sorry, I tried uploading them to youtube but I kept getting a error. I've uploaded them to google drive and checked if you would need an account to view it. https://drive.google.com/folder/d/0B...RqR3c0VzQ/edit

 

Smells like a bad link.

 

Haven't checked it yet. Will do!