Hyundai Repair: 2005 Santa Fe 2.7 V6 idling and running rough, poor power., santa fe 2, vacuum leak

Question
I have a 2005 Santa Fe (180k mile) that started running rough a week ago. I took it to a local shop and they told me that the ignition coil was bad and that I needed new plugs and wires. I changed the coil(s) and the plugs and wires but it still runs rough. I had the engine code checked at a local parts store and it checks out okay. Any ideas what may be causing this, it seed to run okay immediately after changing the coil,plugs and wires but started running rough the next day. Thanks

Answer
Hi, Doug.  If you've got a misfire, it could be for one of many reasons.  While the secondary ignition components (plugs, wires, coil) are the most frequent issues, it could also be:
-- mechanical issue in engine causing lack of compression
-- vacuum leak
-- defective or clogged fuel injector
-- issue in injector or ignition coil wiring
-- engine control module

Is your check engine lamp on?  Was it on prior to the repair?  Does it come on for a few seconds or stay on if you turn the key to the on position without starting the engine?  Normally, a misfire issue would illuminate the check engine lamp.  You say "I had the engine code checked at a local parts store and it checks out okay."  Does this indicate there were no trouble codes stored?  

Since it ran okay for a day after the work, it's possible that the shop correctly addressed the issue but one of the parts installed was defective.  Unless there's a reason to do otherwise, your best approach at this point may be returning to the shop that did the work.  They should be able to warrant anything defective.