I have had my 2.7T Tip PST for 2 months and am really getting to know it. The other day when decelerating and braking, I noticed a distinct "rumbling" feeling and sound. I have heard it several more times and can't decide if it is a problem with the brakes or engine or nothing. I have even tried shifting into neutral and then hitting the brakes, but this rumbling isn't constant. Since my dealer had replaced my wheels at delivery when they were found to be damaged, I checked the wheel torque. I'm also wondering if this would be resolved by using Bailey or Forge. I almost think it is an exhaust rumble, but it has been hard to pin down. I have had turbos before, but can't confirm if this is normal for 2.7T. Any help out there? I hate to waste my time at the dealer to get a "no trouble found".

I don't know if it is quite the same thing though. Turned out it was the ABS kicking in cause I was on loose gravel or sand or I had hit a bump or small pothole. Scared the crap out of me and my wife though.

I kinda came to the conclusion because it kept happening at the same spot on the road that I went down pretty often.

I don't know if this is what you are talking about but hope it helps.

I too have heard that same low rumbling sound. Same car and PST also. It seems to come at odd times and from the front of the car. I don't think it is loose gravel as it has happened to me pulling into my garage. It also happens at a certain intersection where the road has a series of grooves left over from a road grinder. They havn't repaved this spot in over a year so I get it quite often. Sometimes it sounds like a front wheel is giong to just pop off. then it's gone. Right now it's the least of my concerns as I am trying to convince the dealer that the Bosch dump valve should not leak at 1/2 psi boost.

Definitely front end, probably ABS. Always happens as front wheel descends into hole or depression under braking. Sounds real bad, but no other problems.

UniPhone

This rumbling does not always happen, but more often than not. It happens even on the smoothest roads. You can hear and feel it and it seems to come from left rear, although my wife hears it also, so I can presume it might be the right side also. This to me could mean brakes or exhaust, or possibly normal. I'll have to try it again with the car in neutral to narrow down the symptoms. I will probably have to bring it back to the dealer, but am afraid it will result in no problem found. Unfortunately in these cases, sometimes you have to wait for the problem to result in something completely and obviously broken before it can be fixed.