General Exhaust Diagnostic Needed

joshwellborn

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Joined
Dec 12, 2022
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58
Location
Springfield, MO
I've had a 99 2.5L 4Cyl. (160K miles) since October. I've been trying to get it to run quieter. The whole engine shakes and vibrates more than I would expect, but I've never had this motor before. I have replaced the timing assembly (chain, dampers/guides, etc.) I put in new motor mounts. When I get underneath while it is idling, I can hear noise from the rear.
Is that simply the muffler? Is there a way to test a muffler? I don't see any holes...
Also, It is straight piped (no cat or o2 sensor.) I'd like to add that back, so that I can get the engine light off--that's the only code I get.
Should I do a full exhaust kit, plus cat? Is that overkill?
Is welding required, or can I get away with hose clamps and existing exhaust hangers? I've never welded, but I'd be willing to try.
 
Straight pipe isn't helping. Are the heat shields intact? Hanger mounts?

I can't remember at the moment if the 99s had 1 or 2 cats, but a full replacement would probably be easier. I've used Walker downpipes and cats in the past and they have worked ok, though after 100k miles I think the cat will need to be replaced again.
 
My best suggestion to you would be to take it to a competent local exhaust shop and have them build you a new catback.

I've done this many, many times before and usually never paid more than $300. They'll fix the pipe, put a new muffler on there, and at least take care of those issues.

Cats aren't cheap and you're going to want to add one to cut down on noise and so you can get rid of your O2 codes. That being said, unless you can find a good deal on a low mileage used cat, you're going to add quite a bit of money to that bill due to the cat alone.
 
It looks like it has two clamps, one for each end of the muffler. You could probably get it in there, clamped, and then take it to a muffler shop to get it welded, if wanted. You don't want to learn to weld on thin wall tubing, overhead, in cramped spaces.
 
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Straight pipe isn't helping. Are the heat shields intact? Hanger mounts?

I can't remember at the moment if the 99s had 1 or 2 cats, but a full replacement would probably be easier. I've used Walker downpipes and cats in the past and they have worked ok, though after 100k miles I think the cat will need to be replaced again.

I believe all the hanger mounts are in place?
It looks like it has two clamps, one for each end of the muffler. You could probably get it in there, clamped, and then take it to a muffler shop to get it welded, if wanted. You don't want to learn to weld on thin wall tubing, overhead, in cramped spaces.

Understood. Thanks you. I'll do it. I see welders for sale at harbor freight and wondered what a good first welding project would be...?
 
I believe all the hanger mounts are in place?


Understood. Thanks you. I'll do it. I see welders for sale at harbor freight and wondered what a good first welding project would be...?

I have not used the system. Just found it and looks like it had good reviews on Amazon. Could ask a question Amazon of the guys that have installed it.

Good first welding project, making a rolling cart to store the welder and welding supplies.