Kia Optima 2002 2.7 L Engine, Hesitation and rough idle

My wife's 2002 Kia Optima was running quite rough. She told me it was hesitating at low idle and would sometimes not want to idle and would shut off. I immediately suspected a bad TPS (Throttle Position Sensor), but decided to do a diagnostic check with a OBDII code reader to be sure. If you do not yet own a code reader, I suggest you purchase one as it will save you a lot of time and money over the long haul.

So, I hooked up my code reader to the car and turned the ignition on.  It came back with a few codes about cylinder mis-fires (often a secondary code resulting from another failure code).  I found a P0102 code and then went inside to look up its meaning.  MASS AIR FLOW (MAF) CIRCUIT LOW INPUT.

Ah ha!  It had something to do with the MAF or MAF sensor.  On the 2002 Kia Optima, the MAF sensor is located on the air intake just past the air filter, and is connected inline between the airfilter and the intake hose.

The MAF sensor looks like the photo to the right.  There is an electronic connector which plugs into the square part of the sensor which is on top of the MAF sensor.   In my case, I went to a you-pull-it junkyard and took one off of a 2003 Kia Optima with a 2.7 L engine.  I removed the entire air intake assembly including the top of the air filter housing all the way back to the throttle body.  But you may want to get just the MAF sensor (photo to the right).

The air intake hosing can be removed with a Philips screw driver.  Once I replaced the MAF and associated intake hose, the rough idle and hesitation (and also shutting off) of the engine ceased.  The car idled smoothly again and I felt it was safe for my wife to drive.  I did a few miles of test driving to help the computer re-learn my driving habits (I am not sure if the Kia Optima does that, but did so just to be sure.

So, if you have rough idle, the card will not idle and will shut off or if there is hesitation during acceleration, it could be a MAF sensor.  It could also be a TPS sensor (Throttle Position Sensor) so be sure to check your computer codes to be sure.  I have found that it is usually one or the other on the Kia Optima 2002 which causes these problems.

Good luck.

Mass Air Flow (MAF) Circuit Low Input

Read more at: http://www.obd-codes.com/p0102
Copyright © OBD-Codes.com

Mass Air Flow (MAF) Circuit Low Input

Read more at: http://www.obd-codes.com/p0102
Copyright © OBD-Codes.com

Mass Air Flow (MAF) Circuit Low Input

Read more at: http://www.obd-codes.com/p0102
Copyright © OBD-Codes.com