1992 Chevy Lumina 1992 Chevy Lumina - No Start, No Spark

The car is a 1992 Chevy Lumina Euro - 6 cylinder 3.1 liter engine.

I am a bit of a newb with most of this stuff - but I can at least tell you what I have done so far.

After a weekend in the garage (friday evening to monday morning) without taking it out - the car wouldn't start.

I've had problems with the car not starting due to the cold, but it would start if I it got warm enough - that did not work this time.

A few weeks ago the fuel filter was replaced. About a year ago the fuel pump was replaced (and I have been told by my father in law that it sounds like it is working - he turned the key and listened for a sound).

I have tried replacing the front three spark plugs (I can't figure out an easy way to get to the back three).

My father-in-law and I tested to see if it had spark and it didn't.

I sprayed some throttle body cleaner in the throttle body (by recommendation).

I tested all the fuses I could find (found set that covered things like "ignition" and stuff, another set that covered lights mainly, and a set in the glove box that covered stuff inside the cabin) and they were all okay.

Used a computer scanner and got these error codes with these messages:
22 - throttle position sensor is too low
35 - idle speed error
45 - oxygen sensor rich
44 - oxygen sensor lean

At this point I am not too sure what I should do or check.

Let me know if you have any questions that I can answer.