Hmmm... Weird. I would guess a too lean if anything at all. I'm assuming you double checked all the connections and seals, especially the MAF right.Bought a JLT Cold Air Intake a few months ago and after a few weeks of stumbling on start up and rough idling it finally decided not to start this morning. I took it to my local dealership and after about 15 minutes hooked up to the IDS, it showed that the car was over fueling about 30%. We threw my stock intake back on and ta-da, the car runs better than it did and will once again chirping the tires in 2nd and 3rd.
I'm not hating on JLT or any other intake manufacturer, but I would like everyone to be cautious on the intakes they buy and keep their stock intake box handy in case any problems arise, since all cars are not created equal.
If anyone has had similar problems please SHARE. Especially if you have solved the problem without a tune.