Intermittent CEL- got the codes

[cshogen]

Hi Everyone,

I have an issue I hope someone might be able to help me with. The Check Engine light in my 1999 ML 320 has come on intermittently for the last 3-4 weeks, and is now on again.The first time it came on I went to the Auto Zone, had the codes pulled and here's what they were:

PO170
PO173
PO141

The guy there said it was the oxygen sensor that is just beyond the Cat. in the exhaust system. Does that sound right? I have replaced the air filter, which was pretty bad, made sure the gas cap was seated well, put good 93 octane BP gas in it, all of the minor things that could be causing it. No offense to the Auto Zone, but I'm just not comfortable getting my car diagnosis there. I don't want to buy one oxygen sensor @ $159.99 and find out it's the wrong one (I think there are 4), or maybe it's the MAF sensor. Any input would be greatly appreciated.

BTW it has 68k on it and the performance has not changed at all. Still runs like a top.


Thanks in advance,

Chris H.