Hello,
I've had this exhaust noise coming from the front right of my truck for a long time now and I've replaced all the Cats and even took out the front 2. (L shaped ones). I can't figure out what is causing the loud noise. The noise goes away when in neutral and parked. Also it will get louder as i increase in RPMs. I have these codes P1401 P1131 P1151 P0171 and P0174. The noise sounds like its coming somewhere by the manifold on the passenger side of my truck but i can't pinpoint it. Any help would be awesome thanks!

 

Sorry to see you left high and dry. So this noise, is it a puffing sound or more of a constant sound? How would describe the noise?

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