Well some of you have probably heard about my brother and his 1990 Firebird. (Don, I know you have )

Well I noticed a BAD noise coming from his engine the other day. I think I know what it COULD be, but not 100% sure....so I'll tell you what it is and see what people say.

I noticed a couple days ago that when in gear I can hear it making a very noticeable, fast and steady rattling and/or knocking noise. I opened the hood while it was making the noise and found it to be coming from the engine itself and not something around the engine loose, like exhaust sheathing or anything. I don't remember this happening a week ago. Anyone know what this could be, what are all the possible causes of this noise? Another clue could be the fact it doesn't make this noise in P.

I'll let people add their opinions then I'll say what I think it is.

Don, you probably know what it could be.

Rod? take it out and beat him over the head with it bruh

Clutch? torque converter? low on fluid? retarded driver?

Low on oil or tranny fluid?

maybe the hamster is getting tired under the hood?

I'll say something very bad with the valvetrain or the entire motor is loose on the mounts?

Getting warmer...I wanna see what Jr says. This is fun.

By the way you're describing it, I'm gonna guess it'* something he did. Like forget to put oil in it, or put on of the Tornado thingies in there, probably wrong size..

Oil could do it too. We need more info! It'* like saying my car rattles, what'* loose?

Stuck valve?