COMMON ISSUES WITH CADILLAC CATERA - 1997 Cadillac Catera

it sounds alot like the cranshaft position sensor (cps)
i had the same problem with mine, i very common problen with the catera's
hope this helps

K134 Multifunction relay is under the dash on the driver side. When sitting in driver seat, above your left ankle, it is located behind a cardboard panel. Replacing cures many problems with the Bose radio, sunroof, gas and trunk releases, fog lights.

if the engine starts for 1 or 2 seconds then dies I would replace the crank position sensor

most likely a failed crank or cam sensor. Without testing its just a guess.

Fuel pump is powered via the fuel pump relay, which get B+ from ignition switch.

it's the cps (crankshaft position sensor)
it cuts off the power to the fuel pump as a preventive mesure, it's a very common problems with the catera
i had the same problem with my 2000 model

I don't have a diagram, but your problem is the oil cooler underneath the intake on top of the engine. Remove the intake, and the cooler is right there in between the heads. Easy to change once you get the intake off. This is a VERY common problem on Cateras, and the symptom of it is oil in your coolant. I have a 1998 Catera and had the same issue.

Leveling light issues indicate either a leaking air shock or defective control module.

Crankshaft Position Sensor is a common failure item on Cateras, but is not an expensive repair, for these symptoms.

Heater control valve is most likely issue for the first, other issues could be ignition related.