Ok so to start car is throwing Knock sensor code and EGRC solenoid valve. I pulled these codes last week. I went out and bought the EGRC have not installed it yet, but a couple days ago noticed a very different sound coming from my exhaust. I have a custom cat back with a super street turbo muffler and a warpspeed Y. Both under 1 year on the car. The last few days the car has been sounding much louder and raspy. The deep tone is gone at low speed and only heard more at freeway speed. Could the EGRC be causing this or might I have a leak somewhere all a sudden? I have not hit anything that would cause a leak and the parts are still new. Thanks for help in advance.

Edward

 

bump.. anyone please

 

The change in sound is very likely because of a leak. While the exhaust parts are fairly new and probably don't have any holes, a possibility is that something is coming loose. I read a thread here on the org several months back where the guy's y pipe came loose after almost a year. As far as the codes, I don't know if they are related to the change in sound or not. But the knock sensor code tends to accompany a lot of emission codes and goes away when you fix the other codes.

 

i agree with Dennis, u prolly got a leak if the noise became more pronounced all of the sudden.

 

thnx for the answers. tomorrow morning imma jack the car up and see if the bolts need to be tightened. Im hoping its just that...

 

hmm ok so all the bolts are tight as can be. I couldn't find any leaks while under the car. Now i'm at a loss as to what could cause this

 

i just had a similar issue and when i got under the car it wound up being my resonator. The thing had leaks around the base of the resonator pipe. So i had to cut it off completely and replace it with a piece of pipe..so now im straight piped from the cat all the way to the muffler.

 

had no resonator to begin with. When I did my system it was 2.5 custom piping from the cat back no res. with a super street turbo muffler. did that first then a week later added on my warpspeed y pipe. This is really confusing. Could a bat cat be a likely cause?

 

im not going to say yes or no to the bad cat. but the best way to find the leak would be to look under the car with it running.

 

had the car up and running i visually checked for leaks and ran my hand thru multiple places to see if i can feel anything escaping anywhere. found nothing

 

If the car was just idling when you were looking for leaks, it could be easy to miss it. When the engine is revved up, there is more back pressure in the exhaust system. You would probably need a helper for this, but you can hold a rag over the tail pipe which will pressurize the exhaust system and make any leak more obvious. If you have a good exhaust system and you plug the tail pipe real good, the engine will die from too much back pressure.

 

this thread helped me with my problem, thank you