Lately I have been hearing kind of a hissing sound that seems to follow the sound of my exhaust. I have a SIDO flowmaster dumped in front of the rear axle and when I am putting around town I have noticed a slight hissing sound that seems to follow the sound of the exhaust, exhaust gets louder it gets louder I let off and it goes away. I have also been noticing a slight burnt gas smell when I pull up in the garage. Could this be an exhaust leak? I so what is the easiset way for me to check for myself before I go to a muffler shop?

 

What kind of vehicle? What engine ?

 

2006 Lariat 5.4 3V

 

Also I seem to be hearing the noise at the base of my drivier door but that could be becasue that is my closest point to th e underside of the truck. I have tried starting it and just kind of waving my hand around the pieces of exhaust that are exposed but i don't feel anything??

 

Sounds like there is some type of leak near the cat region.

 

That would cause the rotten egg smell right? I smelled that today for the first time but I never got under the truck while it was running before so it might have been doing that for a while???

 

Could have screwed up the EVAP system back there, dumping your exhaust like that. All that heat , specially when your stationary can't be good. The gas smell may be coming from there if the heat screwed up the Charcoal canister vent solenoid (above the rear axle). Your CEL working ? KOEO you should see an illuminated CEL.

 

By CEL do you me check engine light? If so no it is not on. And what is a KOEO?

 

Check Engine Light (CEL)

Key On Engine Off (KOEO)

 

Seafoam it

 

I don't think the heat has done anything. I have the pipes turned down and out to the side. It sounds like it might be a leaky seal around the CAT area like DarrenWS6 said. I think I may just take it to a muffler shop and let them see if they can find a leak anywhere. Thanks for the input guys!