Changed oil in K5 now it diesels when I shut it off???

[GM Man]

Today I changed the oil in my K5 and I put in 5w-30w. After I checked the level and fired it up I drove around for a bit. Then when I went to shut it down it dieseled for the first time. Any thoughts on why it would do this?

Thanks

 

[schmuck]

maybe just maybe but i doubt it the thin oil caused the idle to rise just enoughf to cause it to diesle when you shut it off but ive never heard of that before hey dont feel bad i used to have a car that no matter what i was working on even if i washed it the god damn thing wouldnt start