1986 Pontiac Fiero SE, loud knock in engine?

[jg928s4]

I have a 1986 Pontiac Fiero SE with 79,000 miles on it, I recently invested $1200 for a tune up, brakes, tires, fixed an exhaust leak. It was driving great for about a month an a half afterwards until one day I started her up and this loud knocking noise started. It is still drivable, but I'm not driving it now. The noise is loud when it's idle, when driving it quiets down about 50%, still noisy though. When sitting in the inside of the car, it sounds like someone shaking cans of coins (if you get my meaning, trying to compare sounds). I think it's a flywheel issue, I'm probably wrong, my friend thinks it may be a piston or a rod gone bad.. idk... any suggestions before I spend more money on it?

 

[Larry E]

All you can do is have it checked out. With out actually hearing it no one can give you an accurate reason for this.