Happy New Year Everybody,

I am getting 280 miles from full tank (18 gal). ofpremium grade gasoline on my 98 T5 with manual transmission, with 133000 miles on the clock. The tires are properly inflated and aligned, new spark plugs.The car does not seem toburn any oil. I bought the car in 02/2006 and put approx 18000 miles on it.The car has not received any tune up since I have it. I had a belt tensioner pulley breakdown couple of months ago. As a result, the camshaft went off. Although it didn't kill the engine, it clearly runs rough since than.Periodically, check engine light comes on, and goes offafter certain amount of time/miles.The code was 01 cylinder misfire, when it came on first time.There was general consensus on the forum thatthe valve in the 1st cyl was slightly bent.I am wondering if this can worsen gas mileage to a such degree. or it can be something else? (oxygen sensor etc.)
Is it worth to go to a dealer and have the valve(s) replaced?

In a separate question, can anyone recommend good shopin Pittsburgh area? Thank you!

 

Have the car checked out then.