Hello, so I’ve had the car for about a year and I’ve never heard this noise until a friend wanted me to record my fuel trims at a certain RPM. So I drove the car is Manual for a decent amount of time. I get home, turn the car off.. then shortly after I needed to run somewhere else.
My engine began making the most negative noise I’ve ever heard it make.. and I was able to get a video. This is a 03’ STR with around 114k miles.
I posted this in the Facebook forums and a lot of people suggest Supercharger issues. This issue went away the same day. I’m assuming I may have strained something within the supercharger when driving in manual.
I did purchase the infamous green nylon coupler for when maybe or if I have to update the internals. Any advice or experience is greatly appreciated from you all. The video will be attached.

https://youtube.com/shorts/j0vQa1q38Fs?si=z_HSQxjHg1fgjLgU

 

 

I hope someone else here can tell you exactly what it is, but I think it sound pretty serious and you should not drive the car anymore until that is fixed.
I can tell you that your engine is an interference engine, i.e. if the timing chain should tear for some reason, this would have the consequence that your pistons will smash up your valves (as they use up the same space inside of your cylinders - just not at the same time, if the timing is adjusted correctly).
As a wild guess: your timing could be out by 1 tooth or 2 teeth at the moment, which means that the pistons could already be banging onto the valves...

 

Oh Wow. See, my issue is.. I have no Engine light and the sound went away in that same time frame. I’ve been driving the car and it has not shown any sign or reappearing. In face the car is very strong. My mechanic can help because if it’s not making noise or showing and error, he doesn’t know what to look for

 

It's not a repetitive noise so it's unlikely to be a chain jumped a tooth or something which I have not heard of with these cars and would be much more regular. It's unlikely to be any metal on metal problem with a noise like that.

If it does it again I wonder if it's a misfire from a bad coil pack or one on its way out. Electrical issues can come and go. If it does it again listen to the exhaust and does it sound lumpy and uneven idle. If the check engine light comes on don't panic. Again need to read the codes. If it's flashing MIL back off as this is a bad misfire and you don't want to damage the cats.

 

The Exhaust sounding very Heavy.. as it does most times before my check engine light comes on. Rough even and then the exhaust pops when I rev it.. as if I have a tune. I have a P0174 code.. too lean in bank 2 that comes and goes on its own but the car runs amazing. Very fun. I’ve put a set of 4 used O2 sensors on the car a couple months back.. I’m thinking maybe a brand new one could be the issue.. or I have a vacuum leak.. but I feel like it would be consistent.. not drive like a animal for 4 days and then come on for 30 minutes and go back away

 

You need to use a code reader like an ELM327 and monitor the Fuel Trims whilst you drive to see what's happening. It flags that fault when the trims get to 25% additional fuel added so you could be hovering around there. You don't want to be running your engine lean as you can hole a piston so check this out.

It's an air leak affecting only bank 2 which makes it a bit easier to track down. A smoke test can also help.

 

Well what other test are there? My STFT for Bank 2 floats aren’t 3-5% and my LTFT is always around 18-19%

my mechanic acts like he can’t look at the car unless there’s a light or something to listen to but I can’t show him the issue if it goes away by the time I get it to him.

 

18-19% is bad. Follow the many posts about air leaks / fuel trims.

 

As per JagV8 20% Long term fuel trim is bad and indicates a leak. What is the LTFT value for Bank 1?

Any mechanic should recognise this so also find a new one willing to help resolve issues with your car.

 

It’s that bad, damn. It’ll be at the shop Monday. Bank 1 LTFT fluctuates anywhere around 1-5%

 

One red flag I see is used O2 sensors?
I NEVER put used parts in for something so critical and so cheap.
I would start by installing new O2 sensors.
.
.
.

 

Thank you. I have one brand new O2 upstream that I was going to use, to replace the used one on the side with the high fuel trims (Bank 2)
But bank 1 trims are fine? Should I leave those sensors?

 

1-5% is okay and I wouldnt worry about it. Focus on the bank 2 issue.

 

ok

 

 

Bro just wasted 55 seconds of my life

 

...you sound just like my wife...

PS: If you are a regular on this forum, you will know, that I do help a lot of people, but a life where humour is frowned upon is just sad...
Actually, I think I have not heard anything from Karl for a while - I would have expected that he would send a video link like that before I even could...

 

Don’t compare to your wife bro. I don’t frown upon humor. That, simply wasn’t funny. Regular or not.. obviously this isn’t a joking matter

 

Well, I tried to help - it probably slipped your attention that I was actually the first one to reply to your question. I definitely have spend more than "55 sec" on trying to help you!
And: I am most definitely not your bro!
It was funny - but humour is an acquired taste...