Help still needed on CE Light...

[thumper_svx]

Okay, anyone else any ideas? I think I've got a problem with my car that's driving me crazy.

First, as I posted before, I started getting a Check Engine light that was from a "Crank Position Sensor A Circuit Low Input"... well I replaced both CPS's... the problem's still there.

Then I get a failed O2 sensor... "O2 Sensor Circuit No Activity (Bank 2, Sensor 1)"... firstly... which O2 Sensor is this? The third one?

Now, I'm getting an event every couple of days where my car won't start. Let me describe;

First of all, I get in and turn the key to the run position. I check all the lights and wait for the fuel system to pressurize properly. Probably unnecessary, but old habits die hard. Anyway, then I turn to start it and I get ALMOST a cough out of the car and the dash goes completely black. As I release the key the lights on the dash come back on VEEEEEEERRRRYYYYY SLOOOOOOWWWWWLLLYYYY. Like they're on a fader circuit or something.

After this I can't do a thing until I get under the hood, disconnect the battery and reconnect it again. After this, more often than not I can start my car again and all is good with the world.

I'm at a bit of a loss... this progressive failure of the electrical system in my car has me worried. I am wondering though if these kind of symptoms could be caused by a dead cell in the battery that's on the edge of dying completely but hasn't yet... could that be scrambling the OBDII computer a little into thinking I have failures that I don't? Note that all of these failures have occurred in the last two months! This is a little strange to be coincidence and I'm loathe to replace the O2 sensor when I've been misled already by the OBDII computer to spend over $300 on sensors that don't appear to be bad!

On a side note, the sensors I took off I bench tested when it didn't clear up the problem... they seem to be operating within normal limits.

Anyone any guidance here?????