1994 Club Wagon, 5.8, 231k on the odo. Its always passed smog.

For the last couple weeks I have noticed the smell of exaust fumes in the cab, when I start up the van in the morning to go to work, it lasts for a couple minutes during the drive then dissipates and goes away.
I would like to rule out exaust leak because of the dog house and firewall but I do have the cover off of the heater core. I am wondering what to investigate first, Exaust leak? Or some of the smog equipment failing?

I have had a chirping noise but it has not gotten any louder and I do not notice any change in driveability.

 

I would look for a exhaust leak first. Might be able to get a exhaust shop to do that for free. Be sure and make sure you can watch...
If no exhaust leak then perhaps it is running a bit rich on start up.
How are your door and window seals? Do the rear doors seal good?
Could you be mistaking a oil leak that is burning off the engine as exhaust smell?

just some thoughts..

 

Seals are good all around.
Yes, it very well could be from the oil leak I do have, LOL.
When I get a chance I plan on crawling under and doing a cleanup of the oil and see if that makes any difference.

 

until then be sure and keep your driver window down!