Originally Posted by SRTpowa
I would think if it was running real lean the ECU would pull timing or something, but it still could be running lean enough to stress the motor over a longer period of time. Most power adders reduce engine longevity anyway, but just get it checked to be safe.
This would be my concern as well.
There are a couple of ways of getting a/f... you can add a bung to the exhaust system before the cats... something like the AEM Uego or a NGK A/F gauge... all they need is a power supply.
or
Or you can take it to a dyno shop, and they have a sniffer that goes into the tail pipe to get readings... but that's after the cats, so the numbers may not be all that accurate.