Styx

I had an Xerd header and race pipe installed about a month or so ago and there is a horrible rattle coming from somewhere down there. When I open the throttle the noise disappears, but at idle it is loud, annoying, and somewhat embarassing. I really have no idea what it is and was thinking maybe it is the gasket between the two parts being loose or worn. Has anyone experienced this problem before?

Goldark

Yep.
It's loose. It's most likely not worn, just loose and not tightened enough.

Styx

Well, I checked and all the bolts are tightened. Now I really don't know. I am thinking that maybe the gasket was from the old pipes and that could be the reason for the rattle. There is also a "popping" type noise that wasn't there before all the header and pipes were changed. Almost like a backfire. If, for example, I am driving in 3rd at mid throttle (say 30%) and then let off for a second and then throttle again there is a pop from somewhere in there. It is almost as if there was an excess of fuel. The SAFC was set on a dyno, and of course it didn't happen there. Plus, it is hard to diagnose from in a mechanics shop. Has this ever happened to anyone else?

F5KemoLoco

Pretty sure it's backfiring...removing all the cats and running a straight pipe all the way through will do that. Sound pulsations running down the pipe are no longer being "controlled" by the cats and flow is unrestricted, and that causes the backfiring...pretty sure it's not a big deal..but Im sure the embarrassment can be there...a Lexus should not be running down the street backfiring. ..Just me.

I had the same "vibrations" coupled with raspy metal resonance. I elected to take off the header and keep the racepipe attached.. the sound is MUCH better, power loss is way minimal and there is no more backfiring. The neighborhood also approved.


Hope that helps.

Kemo