Cali emissioned vehicles are equipped with a sensor on the EGR valves plumbing into the back of the intake plenum. A code 71 is triggered when this sensor isnt happy with the gases passing through it. He may very well have screwed things up with his home brew system. My fiance's 89' celica came from Cali and likes to give a code 71 every other day. Her problem is an exhuast leak though. Double check all the connections for airtight and that half the emissions crap hasnt been pulled off. Is the PAIR system still hooked up? Thats the reed valve thingy that pumps air into the exhuast through them tubes that bolt onto the stock manifold. Hope this helps or at least is somewhat informative. ~Darin <img border="0" alt="[Baby]" title="" src="graemlins/baby.gif" />