Honestly I wouldnt know, I did the golf tee trick 2 or 3 years ago, added on the svt header/cat/flex & a lovely fsw stealth, and left the light on for a while only checking to see if any other codes came up every few months. When i first did the golf tee thing there were no codes to speak of, right now there are no codes yet since the ecu hasnt finished doing its system checks yet in the 3 weeks since i last had the battery unhooked.
A co-worker suggested I may have a vacuum leak on the intake side, once the snow clears up i'll go check and see if there are any soft hoses, starting with the pcv and working around the back to see if all is still firm. The car is quite old now, 12 years, but only 55k miles. Hopefully i find a spongy pcv hose and that fixes everything. :D