Kaboom!
 

Hello again!

turned the key to start on wifes 2000 Monte Carlo and blew the upper intake to smitherines.
Never seen anything like it.
So, I'm thinking there had to be fuel/fumes present inside plenum. Leads me to think something's wrong with fuel regulator.
Looks like I'll need Injectors, Fuel reg., Map Sensor, EGR valve (this was stuck in the open position so maybe its the culprit?), Upper Intake Plenum , Gasket Set.

Anyone know about thos happening? First for me!

I have seen this indicated before
 

I have seen this indicated before by a few MC owners Makes a mess for sure. here is a link for you to look at and there are videos and all sorts of info here.
https://www.google.com/search?source...30.tsMXPzy5kBk

Most likely a failed fuel pressure regulator, its a known happening with the N/A 3800.. Should be fixable tho.

My 2002 DE LE, when I got it had a intake blown apart, everybody has told me Fuel Pressure Regulator, however mine has set so long before I got it that the
top end was seized up, I have not yet got mine back together to know, hopefully you didn't put the "Black box" in it, mine had a "Black Box" wired in that made it run rich
and carbon everything up, and its taken some time to clean. Be sure to check your wires, sometimes the exploding Intake causes fires ( like mine) and burns some wiring.

So what did you find out ?

You asking me ? or Parts Hunter? I don' have any idea on mine, just started putting it back together, and I'll probably never really know as I intend to replace all the possible culprits along with changing the intake to the Pontiac aluminum L26 intake so that can't happen again.