Engine management light on
 

Hi all can someone help.
I have just had a new down pipe fitted and had the cats removed, I have gone from a 2inch to a 3inch bore, I thought it may be my MAF as it gets clogged up but it didn't work and the light is still on, please please help

I think you have answered your own question, decatting throws the ecu into unchartered territory spec wise, which isnt the end of the world but does need a little attention to sort. You need the specific CELs (error codes) deactivated on your ecu's rom. Someone local with a tactrix cable should be able to help you.

Thank you so much your a star

What car is it? If you have decatted and gone from 2.5" to 3" your car ideally needs a remap as the air flow is now miles different to stock so your car maybe running lean especially on boost and a lean running car aint good!

Quick search shows an 03 WRX
A decat would be marginal to a lean condition though is enough to throw the CEL codes and the CEL light. Impreza turbos run rich as standard so it really shouldnt have any need to change fuelling for that sole reason. It is always nice to get a bit more out of it though but as I said, not for the reason mentioned above.