Hey guys. I have an 03'lightning with 46000 miles and bought it with 18000. In the past few days I've noticed a rattling noise..sounds like its coming from underneath the truck near the exhaust. Now it only makes a rattle type noise when it's in drive when I'm stopped at a light, slowly reversing and especially when I turn the wheel either way when I'm stopped In drive. But when it's in park and I turn the wheel it doesnt make any noise what so ever and when I'm driving and turning no noise what so ever. Does anyone have any idea what this could be?? Please share your opinions!! Thanks so much. Mike

 

sounds like a loose heat shield

 

^^x2

 

I had a similar problem when I got my truck- Found a few BB size rocks behind the heat shields of the catalytic converters. Or, could be a loose heat shield. I just beat on the exhaust with my hand to listen for vibration sounds.

 

If its not the heat sheild rattling...it could be the Honey Comb in the cat's have come loose and are rattling around. Have you seen anything that looked like a Honey Bee Comb in laying in your d-way or garage. I had an elusive rattle that was killing us for days and I got up underneath and baged on the exhaust with a rubber mallet and there it was. So now, I am running no Cats (we have no emissions inspection in FL). If you have inspections, your gonna have to replace the cats.

 

Hey, OKI... how much louder was your f150 with out the Cat's ?
I'm also in FLA & curious...
thanks

 

Considering that I am running Dynatech longtubes with a Magna-flow back, its not that loud to me.

Now mind you before I deleted the cats if you were sitting passenger back you could not be in the conversation and if I passed you on the left with your window down, you would roll it up to be able to hear yourself think