lrguess

I have an 08 4.0 Mustang and had the FRPP dual exhaust installed recently. I don't know if there is any relevance in this being the cause but when idling in drive (I have an automatic), it idles louder than it had before, mostly when the A/C is on, causing a shudder/vibration. I know its supposed to be different its just a lot louder than before. When I shift into neutral, it becomes quieter (like it should be), and the noise/shudder/vibration decreases substantially (again, like I'm thinking it should be). When I shift back into Drive, it'll get louder again. Also, if I gently tap the gas to get the rpms to around 750 it will decrease. PLEASE help, its really just an annoyance.

drfister

Mine does the same exact same thing when sitting at a light. If I put it in 'N' all is good, when I put it back in 'D', I get some vibration. It only does it periodically, and I havent been able to figure out whats causing it. However, it never has really bothered me. It definatly is from the frpp exhaust though it only started happening after I got it.

Devreaux

Just had my FRPP exhaust installed and have found the same thing when I am sitting at lights. I find that the idle drops for a quick second and I get some vibration.

Larcious

I have an 05 V6 Manual with the FRPP Duals installed. I have not noticed any issues with idle drops or vibration.

The only thing that was brought to my attention while getting it serviced last week, is that the left exhaust is rattling. I suppose it is something you only hear when under the car, as I have been riding for months and have not heard anything. The exhaust may be lightly rubbing up against something, but not enough to make the rattling noise noticeable to my ears.