i installed a megan header and got a code catalyst effiency below treshold and i installed two antifoulers and it took away cel for aroung a month and it came on need help on what to do asap thanx

 

i had the same problem with my AW header and the anit-foulers. Just reset your ECU, let the cvar idle for about 15 minutes before driving again, an then you'll be ok for a while again. I only threw my CEL when I drove for long runs on the highway after no clearing it for a while. Never went off from city/traffic driving though.