What is wrong with my engine? on 2007 Jeep Wrangler

There is a rough idel as well as hesitation when accelerating around the 50 mph mark. Ive had the cat replaced, engine tune up, ignition coil replaced, and trnsmission service rendered and the problem persists. MPG has decreased to around 18.3 from 23 on the highway.

by in Grundy, VA on October 31, 2011
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1 answer 1 comment
ANSWER by , October 31, 2011
It could be many things, unfortunately and without experiencing the problem first hand or being able to do some basic diagnostic tests its hard to say. Is there a Check Engine Light/Service Engine Soon light on? If so a scan tool will be needed to retrieve codes stored in the computer of your car. The codes stored in the computer would indicate where the problem is. You may have a vacuum leak, a bad ignition coil or spark plug or even an engine mechanical problem but it needs to be checked out as the new catalytic converter may become damaged.
COMMENT by , October 31, 2011
Ignition coil replaced last week, and the flashing check engine light was turned off. Hesitation persisted.I