Check engine light on in my 2004 Kia Sedona Ex that I just bought 2 days ago!

I just bought a 2004 Kia sedona ex, it was running great when I got it, and it has 81000 miles. On the way home it kind of sputtered a couple of times, then the engine light came on. I took it to autozone and they said 2, 4, and 6 was misfiring. I called the dealer and they said that it was probably because I didn’t click the gas cap three times. Could that be the cause or do I need to change the spark plugs or coil or something??

I have to assume that the actual codes were P0302, P0304, and P0306. For future reference, if you do want to ask about such things, write down the exact codes as they appear (Pxxxx).

A loose gas cap does not cause a misfire.

If the “dealer” you mention is the place that you bought it take it back to them. Before you do see what the laws are like in your state given that you bought it all of 2 days ago.

Misfires can be caused by anything from bad spark plugs to a bad engine (rare). It basically means that combustion didn’t happen properly in the cylinder. The cylinder needs 4 things for combustion: fuel, air, compression, spark. Lacking any of those will cause a misfire. (Poor compression would be the engine problem).

Now you know why it was traded in…

When you have a multiple cylinder misfire, you start looking at a shared component. In this case that would be a cylinder head or head gasket. I don’t like to start with the most expensive repair first, as this problem seems to indicate so first, I’d recommend looking at the spark plugs.

While they are not a shared component, the misfire is occurring on one side of the engine. If the #2,4 and 6 plugs are very difficult to get to, then its possible that they haven’t been changed if they should have been. If they are 100,000 mile plugs, then its not likely they are the problem, check the maintenance section of your owners manual.

Another shared component is the fuel rail. Look for a leak around it. One more possibility would be a vacuum leak but I’m not sure how that would affect only one side of the engine, I just don’t want to rule it out yet.

The dealers explanation does sound totally bogus to me. I think they are hoping it will go away.

…actually, I am thinking that the dealer hopes the OP goes away.

Giving a totally bogus answer to the OP indicates that the dealer is likely not interesting in providing any repairs and is just trying to stall the OP until the 30 day warranty (assuming that there is a warranty at all) will expire.

If this was bought with some warranty take it back and insist they make it right.
I would have turned right around and insisted on a loaner car or a refund.
If you bought this as-is then you’ll know next time to have an independent mechanic check it out before you buy.

Loose gas cap causes an evap failure, not at all like misfire.