Hello everyone,
I finally got the new intake gasket on my van, along with new spark plugs. The coolant pass-over gasket started leaking and was causing misfires on cylinders 5 + 6. All cylinders passed a compression test. Now when I start it, she idles strong/high for 20 seconds and then it drops down and idles rough occasionally stalling out. No check engine lights at all...I tried looking around for loose connections/hoses but couldn't find anything. I have no idea what could cause this...any ideas?

Video @ https://files.catbox.moe/lpftiu.mp4

 

Sounds like you have a giant size vacuum leak.
PCV valve all good , hose etc.

Slowly and carefully go overall the things you might have disconnected and overlooked on reassembly..

 

@hanky You were 100% right. It ran perfect without the MAF sensor. Made me realize the entire problem was just me running it without the air filter/enclosure. Silly. Thanks everyone!

 

Glad you got it straightened out, thanks for the update.