Yesterday I was playing around with the HPP III, and I think I may have messed something up. First I set it back to stock and got on the freeway to see if it felt better but it seemed slower, it lost the umph it had, but when I floored it, it made a crackling noise as it kept climbing the rpms. The noise is coming from the front of the car somewhere. So I went back home and reprogrammed it to where I wanted it, so now it runs like the wild beast that it is but it still makes that crackling noise. What could it be? Would that cats make that noise when their shot? Anything would help, thanks guys.

 

Have you ever heard the noise before you programmed the car? Can you feel it or just hear it? Does it sound kind of like quiet popcorn popping under the hood real fast?

 

It started after I returned it to stock with the Programmer, but no it wasn't happening before. As far as feeling it, I don't think so, but I can sure hear it and it does sound like that popcorn sound. Why do you know what it is?

 

Could be either a bad cat or detonation, did you mess with your timing at all? When was the last time you changed your plugs and wires?

 

I just changed my wires & plugs about a month ago. As far as the timing goes, the programmer gave me these choices:
Top Speed:122mph, tires are stock
Rev Limiter: I set at 6200 rpm
Thermostat: 160 degree which I have
Shift mph:1-2 +1mph
Shift mph:2-3 +1mph
Shift mph:3-4 +1mph
Shift firmness: 50%

I think that's all it let me do, so I don't know how it could be the timing?
If it is the cat how would I know?

 

If its an exhaust leak especially by the header & cat area you would hear a small ticking almost knocking sound. It would be alot easier if you have another person reving the engine while you snoop around the engine bay. BTW is it throwing any codes?