So way back when, before I started doing any mods, I started to hear a rattle coming from the front of the car during acceleration. I shrugged it off thinking that I would get used to it.

Now, after my flowmasters, C&L, tune, and 4.10's I am still hearing a ratting. I've never heard pinging before but from all of the descriptions I've read it sort of sounds like it. However, I plug my Predator in every once in a while and never have any error codes. The one time I did have an error code was when I accidentally flashed the car with the wrong tune, I got a knock sensor warning which leads me to believe if the rattling I am hearing is indeed pinging, the car would let me know with an error. Am I wrong in my thinking here?

Anyone have any ideas here? Any suggestions on what I can look from under the car?

 

Trying to rule out pinging would be easier than trying to find a ratttle under the car. Most of the aftermarket tunes use a leaner fuel to air ratio and likely advanced timing to get more power out of the engine. This puts the car right on the edge of pinging for whatever octane the tune is based on.

My '99 GT would ping on regular unleaded when it was hot and humid outside, even though it was supposedly tuned to run on regular unleaded. Stepping up to mid-grade cured the problem.

Your logic sounds reasonable to me, however you mentioned it was making the noise before the mods, so it may or may not be another problem. Do you have anybody else who could ride with you to listen to the rattling who knows what pinging sounds like? If it is pinging, then I wouldn't recommend getting used to it because it will eventually destroy the pistons. My other suggestion is to try a different brand of gas.