Help diagnose nasty sound/rattle, 98 trans am, with sound link.
 

Got an A4 98 trans am with 115k miles, mostly stock. Iv been hearing some disgusting sounds coming from under the car intermittently. When I start my car, 3 things can happen:
1. Car starts fine, purrs like a kitten.
2. Will hear a rattle sound as soon as I give it gas, more noticeable in lower rpms.
3. Super loud raspy rattle sound.
Watch "98 trans am nasty sound, rattle" on YouTube
https://youtu.be/063TkMkRk8I

The only solution is to turn off the car and turn it back on. It's a dice roll which of those 3 options will happen. If it starts quiet, the rattling will never come on. Starting the car dictates which option I get and will stay like that until I turn it off.
I will be taking it to the mechanic next week, but if any of you can shed some light on this mystery I would really appreciate it.

Bolt ons : k&n fipk intake, shorty headers( I live in cali), msd wires, loudmouth ii exhaust with custom y pipe.

If I had to guess you have a converter bolt that backed out or you have a cracked flex plate

Agree with above ^

Time to drop the transmission and take a look.

Appreciate the quick replies. Having a general idea helps ease the stress on this mystery.

you can pull the starter and manually turn the flex plate to check for cracks and loose bolts

Although this may be very basic, have you checked the starter bendix / pinion to see if it is disengaging properly after the start cycle? The only reason that I mention is due to the randomness of the issue. Let us know when you figure it out.

Stingerrray

Well just dropped off the car at my mechanic, keeping fingers crossed. Keep you guys/gals posted on diagnosis.

Been hearing soundbytes of this and it's super similar. Might have hit it right on the head.

Starter was the problem. Bendix was getting stuck in there. Luckily flywheel had no damage 😁

Easy fix. If you still have the starter out now would be a good time to put a truck starter in with the 2 long bolts.

What's the advantage of putting in a truck starter?

The truck starter uses 2 longer bolts instead of the 1 long, 1 short on the stock starter. It's not common but the small tab on the f body starter will break and take the outer starter bolt hole on the block out. Happened to me so I've recommended it to people so they don't have to deal with the headache. It's cheap insurance IMO. Any 2500 (6.0) truck starter will work.

https://ls1tech.com/forums/general-m...ock-broke.html

Good to know, I never knew that. I'll probably be headed down that road before long, thanks for the heads up!