so i read on here that running your car with the MAF plugged in will make it throw a code and "run in limp mode". last month before i changed my opti i ran my car for about 3 weeks with the cai and filter off and i had the maf unplugged. my question is when i plug it back in will the code go away and the car run normal again or do i have to reset it?

 

It doesn't actually throw a code (although it could throw a code for a faulty MAF), but when the car can't get a reading from the MAF it defaults to "limp mode" more precisely known as "open loop" where it determines mixture off the MAP sensor and the factory set fuel tables (which are quite rich). If you plug in the MAF (providing it's working correctly) your car should go back to closed loop. You may have an SES light from the stored code though. Easiest way to clear it is to leave the battery unplugged overnight so the PCM loses it's temporary memory.