I have a 1989 Camaro RS with a 305 TBI. I got it about 3 years ago, and about 2 years ago it started making an obnoxious rattle sound. At first it sounded identical to pinging like when you use too low octane gas, but I knew that couldn't be it. I have never used less than 93 octane and the previous owner never used less than 91. Now it has gotten much louder and more metallic sounding.

It only makes the noise when I am in drive (Engine sounds beautiful when I rev it up in neutral) and it sounds worst when I gently accelerate while turning. It also gets worse as the engine gets hotter.

Any ideas? It doesn't seem to be affecting the performance of the engine any, but the sound is embarrassing.

 

what is your timing set at ?

 

Thanks for your reply,

I have no idea. Looking around online at the symptoms for pre-ignition, it sounds exactly like that is the problem. Is there a simple way to check and adjust my ignition timing?

 

before you get all hopped up about pre ignition check your CAT as i bet you have punched a hole through the ceramic of the cat and it is rattleing around in there or it has cracked by itself and is rattleing around in there

 

you have the right oil/ and amount in it right?

 

I have 10w30 instead of 5w30, but I dont see how that could make any difference. I also have it within operating range

 

yeah the oil wont cause that but broken up ceramic in your CAT WILL

 

Did you try to find out where exactly it's coming from? Heat shield is the first thing I'd think of if it's non-engine related.

 

Thats the thing, I can't really figure out where it's coming from because it only makes it while the car is accelerating in drive. When I listen with my head out of the window I am almost positive it is coming from the engine, though.

I guess I could open the hood and run beside the car while someone drives it :P

 

you could try having a buddy gently power brake it while you stand next to it, but whatch out for your toes! Set the hand brake too, Joe

 

yes the noise is do to engine vibration the question is what is rattling it will be your exhaust i am telling you to check your cat... it is 2 bolts to look at the cat then just try lifting it up with a stick or piece of rod if there is movement cut the POS out and get a new one or a nice new 3in exhaust

 

Will do. I am busy this weekend but I'll check it out in a couple of days and let you know what I find.

 

so was it the cat?