How do I know if a dealer is fixing my problem or not? on 2005 Hyundai Elantra

I have a 2005 Hyundai Elantra. There was nothing wrong with my vehicle, but decided to do some prevented maintenance. I brought my Hyundai in for a timing belt. Two days later my engine light went on. They claimed their repair had nothing to do with it, although I did not have a problem before that. They said my spark plugs were loose and the engine light went out, only to come on two days later. Then they put in an bank 1 sensor 1 oxygen sensor, two days later the engine light came on. Then they put in another sensor, did not charge me this time and said it was sensor 2, 2 days later engine light came on again,that light stayed on Sun,Mon, and Tues, my appointment was Wed, sensor light was off, then one week later the light is on again,,had my car towed to the dealer and now waiting for an answer. What should I do? One of the error codes was P0170.

by in Rockaway, NJ on September 26, 2013
2 answers 2 comments
ANSWER by on September 26, 2013
sounds like they are guessing,is there another dealer in you area? if not get a 2nd opinion from a good independant shop
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COMMENT by on September 26, 2013
thanks
ANSWER by on September 26, 2013
Who put the plugs in , that they claim were loose?
COMMENT by on September 26, 2013
so long ago