Ok so ill start of with what I did a little over a month ago. I finally put the 3" exhaust and 42dd intake in the car. Sounds and runs great. noticed a decent increase in performance.

However...when I did the exhaust I couldnt get the post cat o2 sensor out so i drove it without one till i ordered one. I used the 42dd spacer for the sensor figuring the higher flow cat would cause an issue and put the sensor in. A few miles later i got a cel and had it scanned with a code saying no activity so i pulled the spacer out and reset the ecu and presto it worked...for 300 miles. I got another cel and had it scanned again with 2 codes both pointing to that sensor. I called auto parts warehouse and they said it was probably faulty so they overnighted another one. When i took the old one out one of the wires was pulled out of the sensor so I thought ok np the new one will fix this. I put it in, reset ecu and drove it for 25 miles and sure enough cel back on.

Is it possible that its a crappy quality sensor? Maybe I need the spacer now that the exhaust is broke in? Or do you think its a whole different issue?

I did notice a few times that the car wouldnt start on the first try. I would have to try again and it would fire right up and run fine. Im lost at this point.

 

Spacers come in different lengths and openings. Make sure you get the one people have used with the high flow cat to get rid of the cel. Also, you can't break in an exhaust, it's a pipe. If you are having issues starting, change your fuel filter and if you still have issues, change your coolant temp sensor

 

Ok so I had the car scanned. Came back with two codes P0141 and p0142. Looked them up in the book and it says heater circuit for sensor 2 and just o2 sensor circuit sensor 2...Another faulty sensor? The fuel filter is new as of November which i did to solve another issue so i dont think its that but i will get a temp sensor.

If that is in fact another faulty sensor could that cause a false start, meaning starts but then dies. Just wondering if it thinks its going to work then fails so the car dies. When I restart the car the ecu reverts to the stock air/fuel map? Not sure cuz the car is chipped.

The spacer I got for that sensor is from 42dd as is the exhaust and im assuming its adjustable just by how far you screw it in because there are a lot of threads and a locking nut for adjustment.

Personally I think they are a cheap sensor and I should pony up the dough for a better one. As far as a break in the reason i asked was because the first sensor worked for 300 miles before dying without the spacer in it. Didnt know if the cat itself would allow a faster gas flow after it had been driven for awhile.

 

Apnot sure what sensors you are buying, but a Bosch replacement isn't to expensive. The code for cat below efficiency means the spacer needs pushed back further. This won't cause running issues, it's just there to see if the cat is working properly