2005 Spark Plug gap question

[cyrus079]

Hi all,
I have a 2005 4 door Accent sedan (base model). I looked up the gap for the spark plugs, went out bought new plugs, gapped them and installed them. Now I have a rough idle. After calling the parts dealer, they told me that the plugs didn't need to gapped, and that they shouldn't be adjusted at all... new technology?? Sorry, but I forget the brand. Does anyone know if this sounds at all accurate? or should I be looking for another problem?
The car doesn't try to stall, it's more like it's miss-firing.
Thanks

[y2khyundai]

Well I found my gap spec on under side of hood my kids is a 2000 and its gap was .043 in. There ngk and they where at about .025 or.030. Kind of off the mark and it too rough idled in drive. Also make sure you hear the wires click when you reinstall them. The tag is kind of middle left when looking under hood along with vacc diagram.

[The_AirHawk]

There is a suffix on the end of the plug stock number that indicates the gap (in mm) - IF they are "pre-gapped".

What was the number on the box?

[Albinus]

The gap should be 1.1mm, most manufacturers preset the gap - the amount should be on the box. Did you increase or decrease the gap? If your ignition leads are up to the job then a marginal increase shouldn't affect things too badly - but y2khyundai has a point, make sure that the leads are on securely; a dull thump as you're installing them usually indicates the lead is on the terminal of the plug correctly.

Another trick is to wait until the engine is somewhat cool before changing plugs - when warm it takes more effort to remove the lead that can potentially cause damage it. Also be careful with repeatedly removing and installing plugs into a warm alloy cylinder head; eventually the thread will wear (did that to my LC)