I'm new to the forum so please bear with me. I own a 2008 GT/CS equipped with a Steeda CAI, hi-flo cats, Magnaflow X pipe and MBRP axle-backs. I've also installed Ford Racing 3.73 gears. The engine is tuned for 91 octane, Steeda CAI and the 3.73 rear. I started hearing a "busted muffler sound" emitting from the exhaust system. The shop I deal with inspected the exhaust system and found no problem. All clamps and clips seemed to be tight and no leaks were detected. While all of this was happening I had a check engine warning light come on. I checked to see what the check engine was all about using my Diablosport Predator tuner and the message told me I was running lean. Now here comes the weird question...Could the sound I'm hearing from my exhaust be caused by the "running lean" problem or is my shop missing something and the running lean is caused by a leaky exhaust system?

 

Check all the connections on your CAI, lean codes usually caused by
intake air leak, may also cause unusual noise under hard accel.

 

You were bang on. The 3 inch long rubber hose between the intake elbow and the throttle body had come loose. I simply tightened up the hose clamp and the problem was solved. Thanks a million for your advise.

 

Yeah, there have been a few threads about the Steeda elbow-to-TB connections coming loose OR being tightened so much that it distorted the elbow and caused it to eventually slip off. Glad you found it.

 

I had that same problem with my C&L Racer plastic tube so
I took a short flat head screw and drilled a hole thru rubber coupling
tube into plastic tube where it would be covered by hose clamp so it
works as a locating pin, that way I only have to tighten hose clamp
enough to make seal and screw keeps it from sliding apart and no
worry about distorting tube, been running like that for over 2 years
and never have had it slip off.