I took the car to the local AutoZone for a read, and it came back with MAF codes.

I think I'm going to replace the MAF, and if the 2nd sensor goes I'm going to remove the K&N intake and reinstall the original air box.

Judging from my reading here at 6speed, it seems the 2002+ cars do not have MAF issues with K&N. My car is a 99.

I'll keep everybody posted.

 

My car was actually faster as well, I timed it with a stopwatch: .3 seconds off the 0-to-60 time, of course sometimes it was actually slower too! Mine was erratic becuase the Turbo vacuum unit (p/n: 996-123-116-71) was faulty. Now it's fixed so no more lights!