Link to Repair method (all credit to original posters):
https://drive.google.com/file/d/0B5F06FXn8WiIanlKbTQyd2VYQ1U/edit?usp=sharing
https://gorup-sinkovec.net/diy/rattling-noise-in-toyota-corolla-intake-manifold-solved/
Toyota Intake baffle rattling causing engine noise making the car sound horrible and like a diesel engine, fixed using a few screws – so simple.
1. you can do this with the manifold still on the car if you want and put two screws in from the top or you can do by taking the manifold off the car and putting screws in from the other side of the manifold. The screws need to go in at an angle to catch the baffle inside the manifold.
2. I took the manifold off and couldn’t find any rattling component, there wasnt anything loose inside the manifold but it was still causing the terrible engine noise. Put two screws in from behind and two from the front and this has eliminated the noise.
3. Word of caution – one poster claims that a screw broke off on them and wrecked the engine as it got sucked into the engine. Using the screw method will pinpoint the problem, if you want to avoid wrecking the engine by a screw breaking or getting sucked in, please consider going to a scrap yard to get a replacement intake manifold.
Here’s a video overview of the Carter BBD carburetor as found on Chrysler Fifth Avenue, Dodge Diplomat and Plymouth Gran Fury equipped with Lean Burn.