Cadillac Repair: Periodically wont start, cadillac catera, starter fluid

Question
I just recently purchased a 1999 Cadillac Catera.  Every once in a while it doesn't want to turn over.  Usually I open the air filter cover and spray a little starter fluid in and then it turns over.  It seems to be getting worse.  It has died on me a couple of times at stop lights, and then yesterday it died on me and even when I sprayed starter fluid in it it would turn over but then die.  It is acting like it isn't getting any gas.  But then later it turned right over and ran fine like nothing happened.  What could cause this intermittent problem?

Answer
IS or HAS the CHECK ENGINE light ever illuminated while driving the vehicle and or has any other lights illuminated or any messages from the message display center ?.

What work or diagnostics of ANYKIND WHAT-SO-EVER have been performed on the vehicle trying to fix this problem ?.