I had the dreaded check engine light come on, did the "On-Off-On-Off-On" test method.. it spit out the code 31 (or PO443) which is the "EVAP Solenoid Circuit." The description off of 2GNT is "Evaporative pure solenoid / Clogged purge line / Vacuum hose / Evaporative emission canister clogged." Now, I have no idea what some of this means nor where to exactly look. What general problems cause this to show up? It has been there for quite some time, even before I installed my intake and exhaust systems. I am also getting the code 43 (or PO351-2) for my ignition coils. I recently replaced my plugs after having horrible hesitation.. which did fix the hesitation completely. What else can I check to fix this problem? Are these just lingering codes because I have not had my car's codes cleared yet? Or are these supposed to go away on their own? Any help would be greatly appreciated.

First off, the EVAP system can be traced as follows. Its rather long :o At the top of the throttle body, right above the air inlet from the intake piping, you will see a right angled vac line. Follow this line just a bit to the firewall, and it will go into a hard, plastic vac line. Follow that line across the firewall to the passenger side, and it then connects again to a soft rubber vac line. It then connects to some hard steel vac lines along the passenger side frame rail, leading up to the front passenger inner fender. The EVAP solenoid and canister are under the passenger side bumper, up by the framerail. Going from the solenoid, there is another vac line that follows back to the routing of the steel lines along the pass frame rail, then turns down to the ground, by the firewall, then leads under the car, back to the gas tank. You will find a bunch of vac lines and a few other contraptions back by the gas tank, all part of the EVAP system. First thing to do is check the wiring connector at the EVAP solenoid itself up in the bumper in the front. Then follow all the vac lines and thoroughly inspect them for cracks, breaks, loose connections, ect.. Thats a good place to start. To clear the codes from the ECU, just disconnect your negative battery terminal, then re-connect it back up. It will instantly clear the codes when you disconnect the battery. No need to wait for any amount of time, just a few seconds, then reconnect it.