MichaelJ62

I have a 2009 lariat 2wd f150 and for about 6 months now there has been this strange rattling noise coming from under my truck. Everytime I wait and listen for it, it won't do it. I noticed it when I just park after driving or when I'm slowing down while driving. It also happens almost everytime when I'm backing my boat trailer down a launch. It sounds as if it is my gas tank or something around it. It's usually pretty loud on the outside and you can sometimes hear it from the inside. Sorry if I didn't really give enough details but I've never got the chance to stick my head under my truck and listen for where it's at. Was just wondering if anyone has heard of this before or had experienced it.

BCMIF150

My guess would be a loose heat shield. I would try getting under your truck when the exhaust is cold and just shake it a bit. You might get lucky and find the rattle.

ArmyFire328

I'd say BCMIF150 is right about the loose heat shield. Also it could be a skid plate. I had a bent one that would rattle against other parts of the undercarriage, was it's worst at idle.

Edit: Should have read more carfully. A 2wd Lariat probably doesn't have skid plates. Most likely a heat shield.

beknd4pees

heatshield is a possibility. maybe a ujoint?