Re: OBD II code help!
The evap/purge code won't show right away. It is a "pending" code that will only turn on the light after so many start events. This is since the purge cycle, to test the integrity of the evap system, only occurs at start up.
Buy the FSM for your jeep. It'll be the best money that you will have spent on it. All this is explained in detaill.
Check the vacuum hoses to all that hardware that hangs on the driver's side of the intake.
Never run without an air filter unless you consider the engine "null and void", since doing so, if not already, can suddenly make your engine "null and void" if it sucks in something big. Even the introduction of small abrasives (silicon, sodium) sand blasts your throttle body, intake and intake vavles ..given the velocity that they're introduced into the engine. This stuff, some of it anyway, ends up in your oil ..where the stuff the size that can't be filtered out ...just spins around passing through the filter and knocking off lead and tin in your bearings ...and iron off your cylinder walls.
This is why it is recommended to change your oil more often in dusty conditions.