Just came off a 1000 mile road trip. The engine died at the stoplight after I arrived home. (2002 cad deville northstar engine). the plugs were changed about 6 weeks ago and seemed to resolve the problem until now. Help? 140K on the car

A hunt and count question. core/freezed plug.
NO VIN told no RPO code for engine told.
8th digit of VIN is ENGINE CODE VIN :"Y" below.
or vin=9 (8TH)
well even the service manual does not do the count.
it shows some, block and heads.
what you can learn to do is google it.
here is how to do that
I google new rebuilt raw engine blocks for sale.
watch out engine can evolve and even be swapped a newer GEN engine, 279 cu in (4.6 L)
but I will post for DAY new,1996 only
1996, the Northstar engine
RPO code LD8 or L37
lets to LD8
the DeVille Concours was available with the new 270 hp (201 kW) LD8 Northstar V8, and later, the high-output L37 Northstar generating 300 hp (220 kW).
LD8
first hit shows VIN-=Y shows 4 in the 2 heads 2x2.=4
left and right heads outside ends. and 1 rear and front of head for 6 total,

https://www.npdengines.com/product-page/96-99-cadillac-deville-4-6-northstar-engine-vin-y

found with google
die-cast aluminum block!!! SORRY NOT SAND CAST.

A GOOD TECH FINDS THE ACTUAL LEAK FIRST
SEEMS YOU ARE GUESSING,
THE 1995 BACK IS ALL DIFFERENT.

LOTS OF VIEW HERE, ALL FOUND VIA GOOGLING FOR YOU.

https://www.hpmotors.com/cadillac-northstar-v8.html

FIND THE LEAK FIRST, THEN WORRY CORE PLUGS IF AT ALL.

You have a Blown Head Gasket.. It is a 4.6 Northstar Engine. Very Common around 90-105K

It can easily burn that much in a 100 miles without seeing any smoke.
If you check the spark plugs you may find evidence.
It can also leak while the engine is running and not when it is off. Most Northstar engines leak to some degree.

Aircon electric fans not working

sounds like the soleniod to the starter is bad. The starter is located under the intake plenum for the Northstar engine.

poor choice if purchased. The head bolts tend to break and to have it repaired is very costly for they are slender and long. . A 99 Cadillac is too old for they have many modules operating this vehicle and the shocks themselves run nearly $1000 each. Back off on this deal

easy as, 2 bolts at the front and 3 wires at the back remove all and it should come free, the motor is at the front of the tranny it is attached to the flywheel, disconnect battery first

Hello,Your car probably has the 4.6 northstar engine.This (phantom stall) condition is usally caused by 1 or both of the Crankshaft position sensors.I have seen this condition quite frequently on your perticular car.I would replace both of the crank sensors and that should do the trick.you might want to take it to a repair shop due the location of the sensors (front lower part of engine near oil filter) Good luck.

if its not the fuel pump or filter its a computer problem

It's going to take about 7.5 to 8 Quarts. All Northstar engines are like that, so no worries.