Check Engine Light illumination—combined with a lack of power or a stumble on acceleration—may be caused by the throttle position switch (TPS). Kia released an improved part which should correct this concern.Google+
Car Problem Reports
Kia Optima Faulty Throttle Position Switch
Kia Optima Problem
Exhaust & Emissions Affected: 2.7L V6
Average Mileage: 88,899 mi (30,000 mi - 183,000 mi)
Visitor, 2007 Kia Optima, 79,000 mi
Check engine light came on & car would not go over 15 mph. Shut off & restarted & it was ok. Light came on again. Took to dealership & they replaced the TPS sensor for around $400. 11 months later the same thing happens. Take back to dealership & only under warranty for 12 months or 12,000 miles so i was s.o.l. In the process of getting the sensor to replace then this car is going up for sale....has had several recalls & lots of little but expensive things break or go wrong with it since we purchased it. First & last Kia I will ever own!
Car will not accelerate past 1900rpm. Goes about 20mph and 5 mph uphill. it does this intermittently. Not fixed yet
Visitor, 2006 Kia Optima, 94,000 mi
Faulty Throttle Position Switch Cost $750.00 to fix at KIA.
Visitor, 2004 Kia Optima
engine had a hesitation when gas peddle was pushed acted like i had water in the gas, check enging lite came on had it checked /was throttle position switch put on new one now after about 20,000miles it is doing same thing ,had it checked and once again it is the throttle position switch.
Visitor, 2005 Kia Optima, 70,849 mi
car does not down shift to second gear, i was told it was the output sensor. the price for this part is $110.00 can not afford it at this time.
Stumbles while idling in gear. Smooths out when I put it in park.
Visitor, 2010 Kia Optima, 59,860 mi
It's not happening every time, but when it does the Kia is accelerating with a delay or it seems like it stutters before accelerating.
Today for the first time we had the Check Engine Light show up for more than just a few seconds. It was on the whole time we drove it this morning and we scheduled an appointment with the dealership, of course by the time we were going to drive there the light didn't come back on!!!
This is the 4th issue with our Kia in less than 14 monthes!!!
This will also be our last KIA ever!
Visitor, 2006 Kia Optima, 121,000 mi
firstly my check engine light came …few week later, my car started loosing power, would get down from 65 mph slowly decreasing to apprx 20 mph… on freeway, i have to pull over to the side of the shoulder of the road.. turn the car off for a couple of min… they start back up.. car gears up fast almost jets off …then same thing couple exits passed. same thing on the streets.
Visitor, 2006 Kia Optima, 98,000 mi
Same problem. No solution, other than another repair bill.
Visitor, 2008 Kia Optima, 93,675 mi
Idles very slow at startup and sometimes stops if engine is not immediately revved. After engine gets warmed up it's fine.