Hyundai elantra's rough idling

I own a 2006 Elantra with 27,000 miles. Since the summer of 08’ my car has been to the dealer 4 times for the check engine light coming on. 3 of the times it was blamed on the 02 sensor(s)and they were replaced free. 1 sensor has been replaced twice. On the next occasion they mentioned checking for a ‘cracked’ intake manifold-found nothing supposedly wrong and blamed in on a failed 02 sensor yet again. Oh yeah, between the 3rd and 4th visit they also replaced the ignition coil. I really think there is something more serious going on here that they are ignoring, or hiding. The car usually runs strong for a few days,then idles with a kind of tremor, and seems like the engines power decreases.



Any info or advice would be appreciated

If you paid for any of this guessing, you need to find a good (emphasis on good) independent repair shop/person.
What are the trouble codes? If you don’t know, some of the auto parts stores will scan for the codes for you, for free. Bring the trouble (DTC) codes here for more better guessing.

sthis car is under warranty and you should contact the owner of the dealer and ask him to get involved, or contact the zone, or just try a different dealer…you shouldn’t have to pay for teh repair

No i haven’t had to pay for the guessing or repairs,but it is an inconvenience to say the least. I have taken it to stores that check the code for free and it has come up as the 02 sensor several times- along with rich, or lean mixture on different occasions, i didn’t record the codes. The next nearest dealer is an hour away, but i’ll suck it up and drive down there and see what they say.