Vibration/knocking noise under passenger seat

[Robpacific]

Same sound same exhaust. Been chasing it for a while. 2020 explorer st mbrp exhaust. Plastic or metallic rattling sound under passenger’s feet on decel with or without brake pedal. Speeds over 30 mph. It has gotten progressively more obnoxious. Will go check after lunch.

 

[Robpacific]

That was it. Exhaust we pushing forward on decel and rattling against the hanger.

Glad you figured it out. I'm bummed now cause I haven't changed the exhaust.

 

[Foremanrd]

Just in case someone else experiences the noise we started hearing the last couple days. My wife took her ST off main roads and she started hearing a noise she described to me. Today on the highway, I started hearing the noise she described as she drove and I was in passenger seat. At first I thought maybe it was a large paint protective sticker that maybe was coming loose on the roof and flapping. After a bit of detective work, noise seemed from under passenger rear seat area. It is a large felt cover that a nut was not present. Driving off road l, the felt pulled off of the stud and would flap at faster speeds causing the noise. Just in case someone else has similar situation and may be quicker to solve.

 

[Robpacific]

That was it. Exhaust we pushing forward on decel and rattling against the hanger.

So my mbrp kept sliding forward and rattling every three months or so at the center hangar. Today I pulled the whole exhaust out. Took the center bracket off and ground it down in a few spots then reinstalled it backwards. We shall see if this fixes it.

 

[SNYDRO]

Just in case someone else experiences the noise we started hearing the last couple days. My wife took her ST off main roads and she started hearing a noise she described to me. Today on the highway, I started hearing the noise she described as she drove and I was in passenger seat. At first I thought maybe it was a large paint protective sticker that maybe was coming loose on the roof and flapping. After a bit of detective work, noise seemed from under passenger rear seat area. It is a large felt cover that a nut was not present. Driving off road l, the felt pulled off of the stud and would flap at faster speeds causing the noise. Just in case someone else has similar situation and may be quicker to solve.

I had this same issue. Had my wife drive while I sat in the passenger rear seat and look/feel around. I felt/heard it under the floorboard on the passenger side. I crawled under the car after scouring the interior for something bouncing around and knocking into something else. Sure enough the sound dampener/felt cover was loose in multiple spots. It hadn’t popped off the bolts/washers holding it. It’s just those bolts/washers were less than finger tight…. ‍♂️ can you say minor QC miss…. Tightened up the bolts that were loose and I haven’t had the issue since!!

 

[F=MA]

Search this site. Folks replace those shabby connectors with new steel washers and nuts.