3.8 v6 automatic,103,000 miles. My wife had the oil changed the other day. And the guy there asked if she wanted the injectors cleaned.this is the regular place she gets it changed at,and has been for sometime. Changes it at 3000 miles.anyhow she said yes to the injector cleaning due to the miles on the car and it had never been done. So after doing the cleaning,same day or maybe the next,the check engine light came on.

Went to autozone and it was a po420 my question is could the injector cleaner have caused this code, as I understand it its either the o2 sensors or the converter itsself, and was wondering if the injector cleaner fouled the sensors,and maybe with time it will burn away from the sensors or the converter. Thanks.

Edit/ forgot to mention that while the guy was cleaning the injectors there was a lot of black smoke coming out of the exaust.

The events are likely related. Drive the car, reset the ECM, and see if the light stays off.

That's what I was thinking as well.was thinking of running a tank of high octane 92 or 93 fuel through it as well. Thanks for the reply.

Running a higher octane rating than what your engine is designed for won't correct that code.

In fact, the wrong octane rating can hinder proper performance.

Read this short article: HowStuffWorks "What does octane mean?" (http://auto.howstuffworks.com/fuel-efficiency/fuel-consumption/question90.htm)

Thanks CaptainRich.

Just an update that might help others.light went off by its self last night. And after driving all day has not come back on.