The cat converter has started making a vibrating noise do i hsve to replace

check that is not a rock or something between the cat converter and the heat shield. Other than that there is not much you can do except replace the cat because if the noise is coming from inside that means that the cat is broken and will block up the exhaust causing problems

If you are sure that the cat converter is making a noise ie rattling etc the best is to replace it . Check it out and make sure that there is not a rock between it and the heat shield.

your cat is plugged remove it and replace with straight pipe or replace cat

hard to tell but hsve you looked at exhaust and brackets to exhaust?

Common sheet metal rattle sound is the shield on the catalytic converter. If the cat is plugged, damaged or you have an exhaust leak this can also be your lost power issue. Hopefully this helps but if you find other issues, I'll try again. Good luck!

tmac2scorpi, The inner tie rods will not make any noise whatsoever. What you need to check is the axle shafts coming out of the transaxle. You can do this by having someone walk along the vehicle as you make extreme right and left turns. You may hear the clicking noise that you mentioned here. Right now you state that you hear the noise at certain speeds so it may be hard to hear it when you are going slower with someone walking with the vehicle. If the noise is there then the axle shaft on that side of the vehicle will have to be replaced. Good luck with this.

do a back pressure test on the cat-converter check your power steering oil level make sure you use correct oil

It could be all of the things mentioned in your post. A loose/bent/misplaced heat shield will make noise at different engine speeds as various parts vibrate and (((RESONATE))) in harmony with engine speed. Also, a shifted/loose catalyst brick in the converter can be the culprit. If you KNOW for a fact that it IS an internal fault of the converter, it will need to be replaced. Chunks can be broken off as it rattles about and **** sideways downstream in the exhaust. This not only blocks exhaust, but can lead to a dangerous burn-through condition if the piece of hot catalyst wedges in a bend in the pipe where yo do NOT have additional heat shielding.

Have you checked the catalytic converter (also reffered to as simply a Cat by mecanics)? It's the first big canister you encounter on the exhaust line right after the manifold and before the resonator and/or muffler. After a while rust and time can cause either the casing itself to come loose and rattle, or the insides themselves break up and rattle around the cat. And being where it is it often resonates sound around the engine compartment, making it seem the sound is coming from elsewhere than it actually is. And while your at it don't forget to check the flex pipe usually connected to the cat also (some models do not have a flex pipe though). If all that is fine, then the other things to check would be the accessory brackets, wire holders and the like. With vibration and time, sometimes they loosen up and start to rattle. Still nothing? check the suspension parts for anything loose (IE. sway bar links, coils springs, tie-rod, suspension tables). Other than that there isn't much in there that can rattle. If you look at how an engine is built, you'll see that there isn't much inside that can rattle around without causing the engine to fail altogether. I'm not saying it can't happen though, but it's highly improbable. Hope this helps

possibly the cat itself broken up and rattling in side the silencer especially if more noticeable when engine warmed up.