Marty's changed my spark plugs on my 2008 Jeep Liberty (recommended 30k maintenance). Unfortunately it has a noticeably rough idle now. I took it back for them too checkout, they did several tests checking the new plugs for defects, the valves for wear, smoke test, but could not find a reason for the rough idle. They decided to put in another new set of plugs, but it didn't change the rough idle. I was not charged for the extra work or the new plugs. Although they could not fix the problem, they tried everything including calling Jeep tech services. I will continue to take both my cars to Marty's for service when needed.
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