Cadillac Repair Questions? Ask a Mechanic for Answers ASAP
Hello I will help you with your question,
This sounds like one of the heat shields has come loos and needs to be secured. I usually raise the vehicle and tap on the shields to see if they are loose and if I can find anything loose then start it up if I can't find anything. A rubber hammer works well for this.
If this only happens on acceleration then you have preignition and need to clean the engine and do a tuneup.
Let me know how I can help