SES P0130 - Oxygen Sensor

[snwplow]

My SES light has come on briefly, then gone off several times in the last few months... and finally stayed on. I went to Autozone and rented the diagnostic tool to find out that it's the P0130 code, meaning the issue could be a could be a couple of things.

1) either the car is running too rich or too lean
2) or the sensor is bad (I believe in the manifold after reading other posts...)

Is there any way to determine which of these two problems I actually have? And if I have to replace the sensor, is it something that I can do myself? I don't have a whole lot of money right now, so the cheaper the fix, the better!

And should I buy the part online, or in a store like autozone? Looking at rockauto.com I found this part... and THINK it might be the one I need. What do you think?
-ACDELCO Part # 2131551 {#12577588}
SENSOR,HTD OXY(POSN 1) IN EXH MANIFOLD/CROSSOVER $61

Any input or past experience you have would be greatly appreciated!

Oh, and I have the 4.2 I6 - with 153,000 miles... and it's probably the original sensor.

[PROSPHOTO]

This code is more or less a circuit concern, not rich or lean.

Inspect the wiring at and around the O2 sensor for damage :undecided

Otherwise, O2 sensor failure, PCM failure, or an open/shorted wire somewhere.

However, there is a bulletin addressing the code:

install the latest PCM calibrations. As of February 23, 2004, all available TIS2000 PCM calibrations contain O2 sensor diagnostic enhancements. Also, replace the Position 1 O2 sensor with Part Number 12577588, which contains an updated connector.

How long have you owned this truck?
Has the PCM ever been re-programmed?

If you're uncertain, a re-flash with the latest calibration is something that you should consider :yes:

But...the dealer is going to charge you for it :duh:
The better option to the updated calibration is to order a "tuned" PCM from pcmforless.com ; as they use the most current calibrations as a baseline for their tunes, and it won't cost you much more than going to the dealer (but you'll get better results)

[snwplow]

I bought it 3 years ago and it had 100k miles on it. I'm not sure if it's ever been replaced or not. I'm also probably going to be selling it pretty soon... so I'm definitely not going to be doing any 'extra' performance stuff to it.

What does it mean to recalibrate it? Does that mean I'll have to take it to a dealer after all? And what's wrong with the previous calibration that it's had for the past 150k miles...?

Thanks for your input!!