Rattle vibration troubleshoot..

Have a friend drive the car and while it is making this "rattle" sound push on various items around the that area and see if you can change the sound or eliminate it. Once you locate where the sound is coming from insert felt stick on disc between the two offending parts.
I suspect two pieces of plastic have deformed slightly and are rubbing. They just need a little buffer between them.
My girlfriend's Dodge had a similar problem (in a defrost vent), once I located the two offending pieces of plastic, I went to Dollar Tree got some stick on felt discs and fixed the issue for $1.25.

giantcharmer said:

But in returning to idle through first gear mode, the loose rattle vibration kicks back.

Click to expand...

If it rattles at idle, you do not need somebody else to drive this car.

If it rattles at idle IN GEAR WITH BRAKE ON then going to neutral or raising the idle speed by simply pushing on pedal a bit more stops it, then likely to be the passenger side engine mount.

It's a four cylinder and all fours are out of balance to shake, the pass mount lets the engine nose waggle to damp that waggle out with the mount, when they get older and harder they then let some of the shaking pass to get through to register commonly in the dash and front structure behind it.

The rubber in that mount has to be just so exact to stop the issue meaning OEM mount is best, the Chinese aftermarket ones have rubber hard as rock and many will shake like that right out of the box.

Fords have the same issue and wellknown you get the OEM part to stop all of it.