check engine light !??

Well it may be limited help, but you can buy a code reader at Pep boys or a similar place. You can record the mileage and code on a piece of paper and if it's not serious, clear the code with the reader. Then if the light comes one again, read the new code and call your mechanic.

It could be many many things... My 360 threw a code and it was a $300 mass airflow meter.

Since buying the reader this summer I've already used it to diagnose the 360 a few times before the mechanic had me bring it in (he wanted to make sure it wasn't a false alarm, or that an additional code would come up before bringing it all the way in, and he was able to do this since I had purchased a reader), to re-set the CEL in my father-in-law's acrua (loose gas cap) and read a code on a WRX. It's paid for itself already in saved miles to my mechanic and back since initially he would have just re-set and told me to come back if/when it came on again.

 

All cars must have OBD port, or label specifying where it is (if not there), at the dash at your knees by the steering column (look up under dash). I bought an "any" OBD II reader and it works fine with my 360.
Jes

 

I didn't go with the cheapest or the most expensive- the middle cost one. The store will be able to show you them....I bought one that can also detect O2 sensor issues (I think the cheapest one didn't do that...)

On the 360 the port is below the steering wheel, the lower area of the dash where your shins face when sitting in the driver's seat. The 430 probably has it in a simliar area.

 

Didn't you installed aftermarket cats?
that codes is on when the two sensors are reading the same, that means that the euc is thinking that your cat coverter is damage at the bank 1 or have a bad sensor.
try to reset the master switch so the euc start to remap everything again, if that does not work you will need a simulator or get your euc's fooled so it can addapt with your new cats.

 

Did you got the euc's tuned?

 

Wrong!
You will still have the cells on with straigh pipes. Use a simulator or send your euc's back to get that matter fixed for good.

 

If your reader can do it. Take actual measurements of the outputs of all O2's. If any are maxed or have completely invalid readings that will give you another leg up on chasing this down. See if they spike on acceleration and then settle back out. That'll tell you if they are responding at all. Any shop can do this but will lkely charge you and hour or so for the diag time.