Need help to interpret OBD2 codes

'00 Blazer, 98K miles, SES light on steady, MIL commanded ON, DTC's P0131, P0132, P0171, P0300.
I am not a mechanic but I CAN replace parts. Any idea what needs to be
fixed/replaced?
TIA.
Chuck
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On Fri, 11 Mar 2005 23:59:18 -0500, "Chuck Jurgens"

Chuck,
Your PCM is saying it thinks the oxygen sensor (or associated wiring) is bad (the P0131 & P0132). The P0171 (fuel trim too lean) & P0300 (excessive misfires) are likely just symptoms of the first problem.
I'd start with a new O2 sensor. Then clear the MIL & odds are you'll be good to go.
Regards, Al.
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Agreed. P0300 sets when there is an engine misfire significant enough to cause damage to the emission system. But, it also says that an extremely lean condition (P0171) will also cause a P0300 at idle. So, if P0131 (indicating a false lean condition), the PCM will sense a P0171 which in turn also causes a P0300 at idle. I'm with Al, replace the HO2S and see what happens. According to the info I have here, you probably have three, so you'll have to do some testing to find out which one is the culprit.
Steve
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