if it was a drop in and installed properly it shouldn't throw a code.Just purchased an AEM system and fitted it yesterday. After a 10 mile drive the check engine light came on. Car runs fine. Is this because the computer hasn't yet figured out that it's now having to cope with more air being sucked in and needs more time to figure it out? Thanks in advance.
It's an '03 Zetec.
Best bet would be to check the codes and see what the ECU is telling you.