Look at E-Bay Motors parts auctions, there are a few people there selling NIB O2 sensors. I got one for $25+S/H for a Pontiac/GM 3.4L. Go to AC/Delco parts website for the numbers you need then do a search on E-bay Motors and if it is available then you will have a source for your sensor needs...

Also if replacing sensors does not fix the problem then you might have a wiring issue with the sensor in question. Also make sure the scanner is being setup properly, some scanner software will let you check for sensors that are not even available for your specific car so check the settings carefully....

 

Will give that a try...I just want to be as sure as possible that the sensor is the problem, and not the aftermarket cat, before I go ahead and do it. Maybe there's no way of telling unless I change it.

The fact that the light is not permanently on might be a positive - that the sensor is fluctuating in performance and is defective, as opposed to a continual light that might point to a cat problem.

Or maybe thats just wishful thinking that this is a $50 problem and not a $500 one !

 

if its the post cat 02 sensor then the cheapest way to fix it would be a piece of black electrical tape about 3/4" long......


I have an aftermarket cat and no precat on my blazer and i get the post cat code---nothing wrong with the cat, doesnt make the truck run any different. that sensor is just to see if its working properly. the 02 sensor will have trouble reading a high flow cat because of the increased airflow.

im not using the black tape over the CEL, but thats just because im too lazy to do even that......and my tuned PCM comes this week.....[8D]

 

+100 on AC Delco sensors. I have replaced many sensors on my Caprices and other GM vehicles. Delco, while more $$, is the only way to go.

 

Surprise, surprise......a new Delco sensor and $150 later at the mechanics --- and the SES light is back on after 200 miles.

So an expensive experiment later and I know that its the aftermarket hi-flow cat and the o2 sensors that aren't compatible. I did notice an increase in MPG but that must be the air filter and fuel injector cleaning that I did at the same time.

Here's my problem; how can I get a Mass. emissions sticker with that light on. I'm guessing telling the mechanic, "honestly, there's nothing wrong with my car, its just the new cat thats screwing the readings up" won't work. But I had the guy who changed the sensor run the car on the dyno and test things the old fashioned way and everything checked out.

Can I request a manual emissions test next time? Or am I doomed to getting a rejection sticker even though the car runs OK?

Thanks again,

Andy