You should be able to go to a local autozone and they'll pull the codes off for free. Once you have the code, you can search this forum for it - you'll prolly find someone has already had that problem and you'll know what to replace.
MEV Rocket - zetec with powerworks sc
04 BMW M3 Convertible - bone stock
'02 ZX3 - returning to stock
'99 F350 PWS 4x4 Dually - chipped, 4" exhaust, intake, stg1 injectors