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Kia Optima Debacle

Back in Decemeber, I had to have a crankshaft sensor replaced (along with a timing belt), and ever since then, my car has been running worse and worse. At first, the RPM were all over the place. Then at idle it would run at about 300 rpm. If I tried to move too soon, the car would stall. Now whenever I am on the highway and I let off the gas for a second in order to slow down, it sounds and acts as if it is in first gear and takes forever to speed up. Kia told me that I needed a new Coil Pack, but others have told me that all I need is new plugs and wires. HELP!!!

Maybe you do just need new plugs and wires.

If you would tell us the Kia’s model year, current odometer mileage, and the odometer mileage of the last spark plug & wire replacement, we can at least venture an opinion.

It is a 2004 Kia Optima with about 110,000 miles on it. I am unsure as to when the plugs were changed - if ever. The car belonged to my ex wife.

Here’s a simple question:

Was the car running right back in December BEFORE the timing belt and crankshaft sensor were replaced? If it was, you should have complained right away. If it wasn’t, then you should have complained that they didn’t fix the issue.

Is the yellow check engine light on?

You can try the plugs and wires first, since they aren’t very expensive, and then buy the coil pack afterwards if the issue isn’t resolved. One way or another, you’re going to have to make a choice, and try something.

Have you asked Kia why they think its the coil pack, and not the spark plugs and wires?
Share that info with us, and we will give you our opinion on it.


Replace the plugs and the plug wires.
They are overdue for replacement.
If that does not rectify the problem (and I don’t think that it will), then the coil pack is a good possibility.

Incidentally–Is the Check Engine Light on?
If so, is it steadily illuminated or is it blinking?

No, the car ran fantastic prior to December!!! The car started acting up less then a week after getting it back from the Kia dealership. I took it back right away. They insisted that it was nothing erroneous on their end and that the coil pack “just has gone bad due to the wear and tear on the vehicle”.
Yes, the check engine light came on right away as well. As a matter of fact, it didn’t come on until the crankshaft sensor killed my car in December about ten minutes after the car died. I’m probably going to get the plugs and wires replaced soon, because this is ridiculous.

“Yes, the check engine light came on right away as well.”

You are not clear about whether the CEL is currently lit up, and whether it is/was steadily illuminated or is/was blinking. If it is lit up, you REALLY should have mentioned that fact previously.

A steadily illuminated CEL means that you should have the stored trouble codes read as soon as it is convenient. A blinking CEL means that you should drive directly to a competent mechanic, as the engine is misfiring. A misfiring engine can do damage to the very expensive catalytic converter and possibly to other parts as well.

If the CEL is currently lit up, I suggest that you take the car to Auto Zone, Advance Auto, O’Reilly, Napa, or another parts retailer that will do a free scan of the car’s OBD2 system to determine what trouble codes have been stored. Then, come back to this thread to post the codes. Until the codes are known, nobody can really tell you with any degree of accuracy exactly what the problem might be.

OK so I came across this forum and it seems like we are having the same issue. Car is a 2004 kia optima and has about 106k miles on it. Took to autozone and they said 1,3,and 4 are misfiring. I am not sure if spark plugs and/or wires have been replaced. This is my neighbors car. They said that car stalled as they were driving last night. Said it stuttered then turned off. They were able to turn back on a drive a bit more but then again it died. Then car would not start and it had to be towed home. Today i looked at it and it started fine and they were able to drive to autozone for the test. The yellow check engine light is on solid. Any ideas on how to fix? Should we just replace wires and plugs first?

I just have a side question to your issue as I own a kia also. Was this the first time you had the timing belt replaced? If not did you have any issues the other time you had the belt changed?

Yes, i would replace those plugs and wires…the owners manual should say exactly what spark plugs you need and the proper gap, get the right ones, very important.

My guess is that they should have been changed at 100k, if not sooner…it’s a maintenance item, just like tires and brakes.

Let us know if there is still an issue with new wires and plugs.