It could be the AIR injection lines have become loose and are vibrating, mine did that a few years ago it was cracked on the line that went to the cat....its just another thing to look at.

 

if it has a high volume pump, im guessing the bypass valve was actuating. the listing for the mobil filter for the f-body is a small filter. i use the one for an early 90's 2wd truck, it holds about a quart of oil

 

No good Changed oil filter and oil and it remains. Still only does it around 600 RPM only. When I get the RPMs up over 600 it goes away.

Nothing with the high flow oil pump at low RPMs?? I can't see anything loose

 

Will check. Any location? I have to manuals but you may save me some time investigating where these lines run

Thanks!

 

they run down the passenger side exhaust to the cat. did you check the shield for the convertor?

 

Got it. Checked and that part seemed solid. I can't find any cracks in any hoses but the cars pretty hot right now I let it cool and check later.

I checked near the distributor area and the sound is strong there too. Its like its right behind the engine. Driving me crazy! And it surges between 400 and 600 RPMs back and forth like a vacuum problem of some sort

Perhaps I should install bigger speakers??

 

remove the dizzy cap and check the rotor and shaft. could be a worn bushing inside and is making noise. check everything in that area. its not something i would ignore

 

Would I feel the vibrations if it were or would it not be constant instead of coming and going? Like now I can't get the sound to come back. Arg

According to service history the cap and rotor were replaced:

From - Marine Chevrolet Cadillac on 7/31/2008
Mileage = 135,218

Description - Customer states that the vehicle will nto start. Replaced battery and battery tray. Vehicle would start but not run. Traced problem to mass

air flow sensor and electronic control module. Replaced both and tested ok.

1 Battery
1 tray
1 holddown
1 bolt
1 bolt
1 ECM Rem 3.670 194
1 MAF SENSO

Free diag

Recommend all fluids be changed. Several bulbs. Tail shaft seal. Break flush. Rear diff service.
Customer request BG cooling system service. Perform service by remoting rust, sludge, and scale.

Replace plugs and wires.

8x spark plugs
1x wires

Tune 8 cyl motor - replace cap and rotor

1x dis cap
1x dis roto

 

DID you try taking the fan belt off yet?

 

The video is a little better than vauge, but it still may be those lines, there is a line that runs behind the distributor to connect to the drivers side manifold. It could be a couple things, you just have to go one step at a time.