P0302 Cylinder 2 misfire

Asked by Jun 17, 2010 at 01:39 AM about the 2001 Kia Rio Base

Question type: Maintenance & Repair

I have a P0302 fault (cylinder 2 misfire). I replaced the spark plugs just a week ago, and when I checked them today they all still look new, except for the cylinder 2 plug.  It is completely corroded on the top end (where it plugs into the spark plug wire).  I know there are a large variety of problems that could cause a cylinder misfire, however the condition of the new spark plug leads me to believe it is an ignition problem.  I replaced the ignition coil, checked all the spark plug wires for continuity between the coil and the plug, and replaced the corroded plug, yet I still get the P0302 code and the car still jerks and bucks on acceleration.  Anybody have any ideas on what else I can try, or why the plug is corroding so badly?

38 Answers


I have the same problem with a 2003 kia rio po302 # 2 misfire but also have code po113 , I don,t know if they affect one another po113 is a IAT senor that i replaced but all the plugs looked great and wires are pretty new if you fined out anything please let me know and i will do the same bob newjerseyguy64@comcast.net

24 of 24 people found this helpful.

I have the same problem with a 2011 kia rio. This has happened to me on 12/8/12 and 2/6/13. I keep getting the misfire codes...... Kia dealer saying its made gas.. The replaced two ignition coils on the two different cylinders on separate.. I dont trust this car. It is still under warranty.. I want to trade this car.....

18 of 18 people found this helpful.

I meant to say I have the same problem with a 2011 kia rio. This happened to me on 12/8/12 and 2/6/13. I keep getting the misfire codes.. The kia dealer saying its bad gas and only to use Shell gas. IT is still jerks when I put it in reverse and it stalls when I drive... The engine is off now but this is a bad sign off it is already messing up and it is still under warranty.. smh... I'm writing to the coporate office...

12 of 12 people found this helpful.

exact same thing happening to me KIA RIO 2011; when I'm at red lights it jerks and shakes for no reason I can figure out; also has the P0302 code; still under warranty and already has problems. Ridiculous!

13 of 13 people found this helpful.

i bet it is the fule fuilter

5 of 5 people found this helpful.

I have the same problem with my 2003 Rio. I changed all the wires, plugs, coil pack, and fuel filter! and still having the this problem!!

14 of 14 people found this helpful.

i have a 2009 reo, my no.1 misfires,i changed plug, put 1 can injection cleaner in ,2.5 gal fresh gas , still have problum, i m trying a new injector will let you know, sad i drove this car 14,000 miles now, im retired, and truble al ready.

8 of 8 people found this helpful.

I just had my engine rebuilt on my 2006 Kia Rio 12,200 miles ago, and randomly experienced misfires a little while back that seemed to go away after letting the car sit overnight. Now it happened again, just randomly as I accelerated from a red light, and am in the process of trying to figure this out. Really makes me mad!

20 of 20 people found this helpful.

I have a 2011 Kia Rio and the same exact thing. it was driving so perfect and one day it just suddenly started to jerk and almost konk out. The check engine light came on, and it appears to be running smooth again, the light is now off, but I am paranoid about what this could mean.

24 of 24 people found this helpful.

I have

5 of 5 people found this helpful.

I have a rio5 2009 and am also having the same problems with cylinder #1. I've had it in two garages in our home town and just brought it to a Kia dealer ship the other day. They replaced the plugs and were going to replace the coil but I already had it done before I went in and I am still having the excat problems. The light came on later that day I had take. It out of Kia garage. I've spent so much money on this problem but yet I can't get it fixed. If anyone has any ideas it would be greatly appreciated. You can send them to chbishop21@hotmail.com

11 of 11 people found this helpful.

My 2009 kia rio is misfiring on 3 of its 4 cylinders and Its only at 52000 miles. According to the information I have compiled while researching this problem I have found that voluntary repossession of the vehicle and declaration of bankruptcy are likely the best course of action. The engine is gone yet I still owe $12,000?!? I'm getting lawyers.

3 of 3 people found this helpful.

I inherited a 2002 Kia Rio that was throwing codes that (Autozone, NAPA, and O'Reilly all agreed) showed either had to be Emissions related or the Crankshaft Position Sensor. Everyone agreed the most likely culprit was supposedly the latter issue. It turns out, after taking the car to a local service station, that one of the plugs for the ignition coil packs was broken. Since there seemed to be no schematics of this car, except for the electrical system, I ordered what I thought was the correct part (Ignition Coil Condensor). After spending $33, it turned out to be the wrong part. Although you won't find this information anywhere, the part doesn't seem to have a name, but is referred to as the "Ignition Coil Connector" and is a 2-way female plug coming from the Main Wire Harness that plugs directly into the Ignition Coil Pack. If you try to find this at any of the above mentioned auto parts stores, they will all tell you it is a dealer only part. If you call the dealer, they will try to sell you "Condensor" that I mentioned previously. If you finally give up and just take it into the dealer, they will charge anywhere from $200-500 to fix this. If you get disgusted "like me" and decide to continue your investigations, making several trips back and forth from your local service station (who is actually the most helpful) then you will eventually discover that these plugs can be purchased online for about $10. Here are the signs and symptoms of what I was experiencing: engine misfires, check engine light (codes - "see above"), difficulty starting, idling very rough, running very rough up towards 60mph (won't go over 60mph), speedometer stops working momentarily, car will stall if I don't give it gas while idling. These symptoms vanished when they taped the broken plug back into place. This is currently where I'm at while I wait on the correct plug to be ordered. I'll confirm everything in another post once I've got this part replaced correctly. I think I will go ahead and have both of these plugs replaced, since there seems to be a problem with them falling apart.

31 of 31 people found this helpful.

Another thing I forgot to mention. This plug may not necessarily fall apart and look like mine did in the photo I posted. In fact, this part was already malfunctioning before they removed it, at which point the plastic housing surrounding these female receptor (prongs) literally crumbled in their fingers. They had to tape it back on, which is why this photo is kind of difficult to comprehend (the tape is hiding the wires coming off the back of this plug that are wired into the Main Wire Harness). This damaged connector will have to be removed so that the new one can be spliced in its place.

6 of 6 people found this helpful.

I have a 2009 Kia Reo, starting in March 2013, first coil went out under warranty. Then Oct 2013, the remaining 3 coils went out, I was not out of miles for warranty but was over 5 year, by 3 months, they want almost $ 600.00 to fix, I explained that this is a product issue, this Is a 100% product failure, if you have 4 coils and 4 fail, and you are under 60,000 mile you have a product issue. This car is used only to drive to work, 5 years old and under 60,000 miles there is a product failure.

3 of 3 people found this helpful.

Correction to previous note last three coils went out in October 2014.


Here is an update on my 2002 Kia Rio. It turns out that the Crank Position Sensor was also bad (wires had been slightly cut). This was discovered after the check engine light came back on after getting it back from the shop. The mechanic had told me that even after replacing the coil pack connector it still retained a slight knock in the engine. Well, as soon as I took it out on the road over 50 mph, it started misfiring quite heavily (wouldn't go over 55mph). That's when they discovered the wires had a very slight cut close to the crankshaft position sensor. After replacement it ran like a million bucks. Now, just a few days ago the check engine light came back on again. "What now?" It has been running great, even with the check engine light appearing, but today the speedometer stopped functioning for about 5 minutes, then came back on. Again, no problems with engine or transmission that I could tell. Only the the check engine light and speedometer. So, tomorrow I take it back in to try and get this last bug worked out. Probably just electrical, possibly the speed sensor, but the codes all point to other things (P0128, P0456). I'll post my findings when its all fixed.

9 of 9 people found this helpful.

I have a 2002 Kia Rio. About a two months ago my car would slightly skip and misfire. My engine light came on following that. It threw several codes that i was not aware of when i bought the car. I replaced the crankshaft position sensor. The car would act right for about one week and then start to misfire again. Then the check engine light would come on. Plugs, wires (several times), fuel filter, coil pack (several times), crankshaft sensor, camshaft position sensor, ecu (computer), both 02 sensors, knock sensor, mass air flow sensor, new battery, and timing belt. Not including the water pump when it went out a while back. We have put all of our money into this vehicle and we have still not resolved the problem. Not one garage that we have taken this car to can resolve this issue. It misfires continuously now. It used to only misfire every once in a while and after we would change the part and clear the code, the car would run fine for about a week, but would eventually start misfiring again. I made a mistake in buying this car. It won't go over 50 mph and takes about 5 minutes to get to 50 mph. If anyone has any answers email me at lsmith39@ju.edu

5 of 5 people found this helpful.

Possible collapsed exhaust or plugged catalytic converter.

3 of 3 people found this helpful.

Huge lessons they don't want you to know about: Multiple misfires indicates the timing is off as you should really just get one misfire/one cylinder and rare two at the same time. Probably a worn out tensioner allowed the belt to slip a tooth on the cam. Otherwise the other huge huge lesson is that you need to change your spark plugs 72% from what they say is the maximum life of the plug because otherwise you mess up your $2000 catalytic converter. More planned obsolescence. Hillary says you overspent. In the old days they say the cat will never fail unless something else does. Hello, you overspent

2 of 2 people found this helpful.

My 2010 Rio has a coil go out every few months, I deliver pizza so I put massive miles on it. I notice that the bad coil has no springyness when I take the 10mm bolt off. New coils have a spring that contacts the spark plug and you have to push it down on the plug, then bolt it down. I`m suggesting that it`s the spring in the end of the coil boot, that looses it`s springyness from high heat. Then the contact is weak and the coil burns up from heat and electrical charge overload. For example the coil would misfire, then after sitting in cold weather for 30 minutes it would then work again, eventually I had to replace this coil. In Teas heat they dye quick.

6 of 6 people found this helpful.

Sorry that`s Texas heat, not Teas. If anyone has similar problems note them hear. Thank you.


For those of you with Rio's new enough to have individual coil packs (one for each cylinder) they are amazingly easy to replace all you need is a socket wrench and a 10 mm wrench. There is a video on youtube that shows you how. first, remove the engine cover (3 bolts) right under the cover are the coils. remove the wiring by pulling out the tab on the connecter and pulling the harness off the coil, then remove coil by removing the bolt and pulling the coil out. The resistivity can be checked to ascertain whether or not the coil is bad. for 2011 the primary is .75 ohms +/- 15% and the secondary is 5.9 kOhms +/- 15%

4 of 4 people found this helpful.

Hey 57, you ever do a compression check on your car? Might want to look into that.

2 of 2 people found this helpful.

I have heard that there is a computer update that will keep the kia rios from "getting confused" and getting stuck in second gear. Anyone else heard anything about this?


I had one plug that had corrosion in it, coil over the plug, and it was scary removing the plug as if it were stripped threads. Water from the hose got in there and while trapped it corroded that much more.


I have the same problem with my 08 kia rio. my code is P0301 and I don't know what to do next. please help if you know.

2 of 2 people found this helpful.

OK I Now believe that you should change the plugs at no more than 80% of what they say is the maximum life of the plug so save the catalytic. You probably got water in there that then turned to rust making the contact to cause the misfire. Or you probably blew out the gasket so that you're compression is wasted. Stuck in second gear is because the shifter assembly has micro switches that break. They are sold on Ebay from Hong Kong. You'd have to soldier the wiring. I'd highly recommend the any car with that E series transmission. full on weak transmission for a six cylinder for sure.

2 of 2 people found this helpful.

Another update. I finally took this in to the Kia Dealer about a week ago. They repaired an oil leak that was getting into the spark plugs, fixed the blower so the heater works again, and then I replaced the plugs and wires with NGK brand. It ran noticably better for a day or so. Then a misfire showed up again. Now I have to take it back tomorrow for a recall on the fuel distributer, so I'll have them reassess. The computer update was also a recall, come to think of it. I'm still experiencing random electrical issues (missfires, dash lights off/on, A/C compressor functional/then non-functional, complete lack of acceleration and stumbling, rough idling, speedometer on/off. The performance really took a nose dive when I attempted to reset the ECM myself, thinking that I needed to after replacing the plugs & wires myself. Tomorrow I'll find out what else they try to sink me for at the dealership. This car was actually given to me, but I have more than paid for it in repairs already!!

1 of 1 people found this helpful.

Got my Rio back from the Dealer today. They performed the fuel distributer recall replacement (except for one part on back order), and replaced a faulty ignition coil assembly that was responsible for reduced spark in cylinder 2/3. Now it runs like a million bucks!

2 of 2 people found this helpful.

After reading everything you said, @flippinthemadstyles I don't know where to start): I have a really rough idle, it feels like it misfires sometimes at a stop, but no codes for misfiring. only code is p1166. the idle is very smooth if i hold my foot barely on the gas pedal, but if i hold it there too long and let go the car can shut off... I guess i'll replace the coil ignition connectors that you told us about... Having trouble finding them though. Could you show me a link to them?

1 of 1 people found this helpful.

http://www.fixya.com/cars/t9597279-kia_rio_fault_code_p1166 here is the link you nee . the code 1166is usualy the idle air sensor, some times the throttle position sensor. BOTH EASILY CLEANED WITH THROTTLE BODY CLEANER.


If the same part is replaced over and over,and the plug is corroded,then that leads to a whole in the head gasket or cracked head where fluid is seeping through. Granted you may not see fluid before starting the car,but if you take the plug out,start the car,fluid might be seeping through. Coolant is high pressure,and any little hole or crack in the head gasket or head will corrode that particular area over time. And these techs at dealers,well ......idiots to say the least.

Good lord! So what is the final fix? I have to change the alternator now too, but mine is cylinders 1 and 3 that keep blowing coils. I'd like to get it fixed before I give this car to my nephew. It would be hard to believe that all these cars have holes or cracks in the heads. If it's a manufacturing issue with the threads in the spark plug housing, could that cause it? Maybe carefully goop the plugs before putting them in? Dammit man, I'm lost on this one.


Kia Rio 2009, 3 Spark plug coils went bad all at the same time at 62K miles, replaced all 4 coils and new spark plug. Car idles fine but get no power to get car go pass 50MPH. It's a 5-speed manual. Also replaced downstream O2 sensor with no luck. Was there a recall on this car? Thanks in advance.

1 of 1 people found this helpful.

I have one not manual but 2009 kia rio and it was my Cadillac converter stopped up

1 of 1 people found this helpful.

asanford, Which cat was plugged? the one at the manifold or at the exhaust? I have had the misfire cyl problem too, I've swapped coils, to no avail, found my downstream cat was plugged so I punched it out. It had no effect. The engine fires but bogs and dies with any load or gas given to it. I've tried replacing cam shaft sensor, crankshaft sensor = no effect. Buying new cats for a "maybe" is kinda scary. Anybody have success fixing this by way CAT converter?

Have 2004 Kio rio, had miss fire problem couple years back and found one of my spark plug insulators inside the engine housing was cracked with the plug wire sparking in the housing. Replaced insulator and fixed problem. Have had issues when I start it up lately running rough, then I shut it off and it starts fine. Twice in the last two weeks after driving some distance in the heat with the A/C cranked I have had issues miss firing (especially stop and go/slow traffic). When starting the car after stopping it would be trying to run on one cylinder and shut off each time. After sitting for a bit it would run fine. I have picked up a coil pack and will see if it makes a difference (hard to tell cause it doesn't do it alot). I have noticed it is hard to get the car cool when stop and go driving, especially in the heat of the south.

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