noisy rear suspension

Two years ago I purchased and installed an SLP Level 1 suspension on my 1995 Z28. I also installed ZR1 wheels with G-Force TA KD tires. Ever since, I noticed a rattling noise coming from the rear of the vehicle. It sounds like it's coming from the lower control arms or possibly the panhard rod. Anyway, I've checked and rechecked everything multiple times since and I can't get the noise to stop. Any suggestion on how to fix it?

try tightening the spare tire or the jacket!!!

The spare tire is tight. What do you mean by "jacket"?

the jack is right nent too the spire under the carpet. Just trying to give you some ideas you might not have thoought about.