Hi i have a few friends who own mustangs and they have all upgraded as u know, what 98% of all owners do, intake and exhaust, no a few of them noticed the check engine light no after adding the new intake. Both are running cat back systems. IS a tuner chip needed to adjust for more fuel to enter the engine to make up for the extra air. I think the engine is running lean and this is what is setting of the sensor. comment back on solutions to this problem.

 

Have you scanned the codes?