(PAST REPAIRS)
I had the O2 sensor 2,2 go out a few months ago and replaced it with no problems.
Other replacements over the years was the crank shaft sensor and last year the fuel pump.
Over all fairly happy with the car.

NOW
O2 senors bank 1,2 and 2,1 came up with heater problems and the car is running rich.. seems rich when it first starts then not so much once warmed up. (kinda makes sense if the O2 senors heaters aren't working)
Changed plugs and both sensors (Bosch parts 16066 & 16064) with the battery disconnected to give the thing time to clear the codes.

I am now getting (after driving 5 miles) an O2 sensor not responding for the two new sensors but the car now idles great and runs good except I can still smell fuel at warm up and I still get the too rich code.

Turned key but not started. Got a clicking noise near the air filter.... sounds like something opening. (also whats that quiet whistle?)
Tested the voltage going to the O2 sensor 1,2 heater and it's 8.3 volts.
Tested the ohms of the heater and its 8.7
Tested the O2 sensor and got .2 volts (car still hot because it was recently driven.
Checked all fuses and they are good (any under the dash to check?)

What next?

 

Latest update. I took it to a mechanic and they put it on their computer. Turns out the thing is throwing many different codes at different times. They believe that its the ECM since ALL the parts the ECM claims are defective test out in perfect working order.

Sounds like it's time to get rid of this beast.

 

Why not just get rid of (replace) the defective(?) ECM ??

 

I've read several posts in other forums that say that only the dealer can replace and program the ECM. I can purchase one on E-bay for 20-60 bucks but it will most likely still throw out codes because the odds on my car having the same features as the one it came out of are slim.
New ECMs supposedly come blank that's why the dealer has to program them. (I have no clue if the rumors are true)

(parts cost rounded for simplicity)
Camshaft sensor was $150 year 2008
Fuel pump was $250 year 2009 ($700 'cause I had it done)
bank 2 row 2 O2 sensor was $100 year 2010
Bank 1 row 1 O2 sensor was $50 year 2011
REmanufactured ECM $300ish repair needed now, maybe if I can do it.

I'm not counting the bank 1 row 2 or bank 2 row 1 O2 sensors I replaced last week because I replaced them without testing them because the other 2 were an easy fix. I probably replaced two working sensors.. my own fault.

It could still throw out a bunch of codes of things that need replaced once the ECM is repaired and able to read the devices properly.

Next it won't be long and I'll need an EGR valve $100

The car is a 10 year old car. It has started needing repairs. I keep up on it so I do not end up on the road dead in the middle of no where like I did with the camshaft sensor, that's more important than the parts cost.

I can afford a new car. Saturn does not make new cars so I will have to find another company I trust. Currently that is Tesla and in 18 months I will have a Model S that I have reserved. If my intuition/research pays off I will have another ten years of happy driving like I did with my Saturn.
If Saturn still existed I'd be at the dealer now buying a new one.

I can even keep my Saturn with this... in Missouri
http://www.dnr.mo.gov/forms/780-1972-f.pdf

As long as I drive it less than 12,000 miles every two years I can get a waiver for the emissions which most likely won't pass without the ECM working properly.

If you know for sure that I can buy an ECM for a 2001 L300 fully loaded and replace it without needing to take it to a dealer where they will stick it in my @ss for programming, then I'm up for the repair.
Also it would be nice if I knew all the wire test points and readings so I do not plug in a new ECM and discover that the old one was fried because the hot wire to the (yin-yang) became grounded and was not repaired before replacement.