I have noticed lately, that when my truck gets warmed up, it has a smell that reminds me of natural gas or propane. What would make this smell? Do I need to be concerned about anything?

 

Can't be sure of how you interpet smell but if it is sort of sweet in the cab look for a leaking heater core. Anti freeze is sweet smelling.
Look for a leaking heater hose above the rear cylinder #4.

 

Im not sure if its the same smell I had on my 99 when the heater was on. But it was my resister under the glove box. They are bad for melting the wires going to it and then giving off a foul smell. Its hard to see but it behind and under the glove box. Feel for it there two bolt 8mm I think its been a while. Unbolt it then follow the wires to the pig tail and unclip it. If its burnt it will be very obvious. Mine had a hole burned completely through it. Hope this helps.

 

That's a converter going bad.

 

what kind of converter do you mean?

 

Thanks for the suggestions, guys. I'll check those things out.

 

Catalytic converter

I had one go bad on a different truck years back, smelled like sulfur

 

so you think the cats are going bad? is there a way of deleting them without setting codes or something?

 

Yes, but it's not cheap and you have to find a tuner that will do it and then custom tune your truck to run without.

I would sell your old cats to a salvage yard. You should make between $150 - $200. Use that money to purchase new High Flow cats. New high flows are about $170.

It's a good time to run headers at this point.

 

Thanks for the good info! I would love to replace the whole exhaust right now with performance, high flow parts, but the budget won't really allow anything that isn't absolutely nesesary at this point. Are the cats in their current condition causing any problems? is this something that I really need to address?

 

Actually, it's not hurting anything unless your cats are plugging. The Sulfur smell or Rotten egg is not an indication of an engine concern and will not cause reduced driveability or durability of the engine or any of its emission components. The odor is caused by high amounts of sulfur in the gasoline. Get your gas elseware, see what happens.

If your cats are deteriorating and/or plugging up, you'll notice them getting hot or glowing in the dark. They "Ting" loudly after shut down.

Yea, try switching Petrol Stations first and keep an eye on your converters.

 

OK, thanks. Actually, this smell isn't sulphury or rotten eggy, more like propane or something.

 

Then its not the cats.

 

Well, spill it .. What is it ?

 

I still think it's fuel related. Converters will store fuel related /emission odors, right?