I have a 1999 Chevy venture van,when I start the engine in the morning I usualy hear funny sound from the exaust as the engine idiling, this lasts for afew seconds and then it stops and then it starts?
Heat shield ? Check to to see if any welds have come loose on any.
If your van has air shocks in the rear like mine, you’ll hear a funny noise that comes from the rear end which would be the air pump filling up your shocks at start up. That sound could sound like it is coming from the exhaust. If your shocks are leaking, you will hear it repeat itself when they get to a certain low level. Look under the rear end of the van and look at the rear shocks. If they are oily, they are leaking. If you throw some 300 lb. passengers back there, you’ll really hear it! You can choose to replace them with regular non-air shocks if you want. My 2000 Venture did the same thing. I guess it depends on what that funny sound sounds like.