06 Honda Civic auto 103000 miles getting great mileage on highway (43mpg on a 500 mile trip) but only 20-28 city. The idle is rough at times and engine ticks when it is first started in the morning. Some one sugested adjusting the valves but I am not shure if it would negatively affect the great mileage. Are there services I should or should not have preformed when it goes in next? Timing belt, water pump, plugs, trans flush etc...

On the side of the throttle body.

Hi. The most common cause that I have found for an " only idle misfire" is low compression. The engine needs at least 100 psi of "dry " compression to idle smoothly in most cases and if any cylinders are higher or lower by more than 20 percent of any other cylinder, you will also have an idle misfire condition felt. Should you perform a compression test, make sure to disable the igntion system completely, not just move the ignition wires out of the way as you will still have spark and the fuel injectors will still inject fuel in nearby proximity to possible ignition source. Always perform two tests, "dry" and "wet" compression. "Dry" is warm engine with spark plugs removed. "Wet" is after performing "dry" test add a few drops of light oil into cylinders and perform compression test again to see if the number rise. If they rise, you have worn piston rings or cylinder walls. If they do not rise, you likely have worn valve seats, misadjusted valves, or head gasket issues, possibly cracks in the cylinder head. If you need to know how to compression test with a tester in detail, message me back and I can help. I'm assuming you may already know due to the fact you state you replaced all the parts likely by yourself so you probably have strong technical merit.

One tank of gas is not enough to compare mileage. Or are you saying the computer's readout of mpg estimate is showing less? Try a tank or two of premium and see if that helps. Keep track of gas mileage. Driving techniques have a lot to do with gas mileage, as does long trips vs. short trips, highway cruising vs. city driving. For best mileage, do regular maintenance and keep the car in top running condition-good spark plugs and clean filters and clean oil ! Attend to minor problems before they escalate.
If you want to check actual miles per gallon, start with a full tank. Write the odometer reading down, and go. Everytime you put gas in, write down the amount. When you are close to 1,000 miles from the time you started, go fill the tank and include that amount of gas to your previous list. Now add up all the gas used and divide it into the miles to get miles per gallon. (976 miles/31.8 gallons = 30.69 mpg ) . Only one tank will skew your numbers, might be off cause the tank was filled more to the top than the previous fill-up. About a thousand miles of driving will give you a very accurate figure of miles per gallon for your car.

http://groups.yahoo.com/group/villagerquest/

what is your milage now, how many miles, how does it run, city or hwy driving??

I have a 2000 malibu ls, and it gets about 27 in city to about 32-34 on open highway.

I have the same issue of low gas mileage. My 2008 Kia Rondo with V6 (2.7Lt) gets 20-21 mpg in average. Even for highway mileage, it is around 21-22mpg. Very poor gas mileage. Disappointed. I hope it would improve in the future.

It's actaully a timing belt, not a chain. But the mileage recommendation i believe is 60,000 or 90,000 miles.

My Answer:

Poor gas mileage can be a result of many many things.

First of all you need to find out what is the factory normal gas mileage for your model year Jeep SUV. It should have said on your window sticker if you bought it brand new. If you are a 2nd or 3rd owner then a Jeep dealer would have info. Google search will tell you as well, and only takes a couple minutes to find.

I did a quick Google search and for a 2003 Jeep Grand Cherokee with a (4.7L V8 engine) the average mileage is roughly 14 mpg.

Not sure what engine you have as to options, etc?

How you drive will greatly change that number up or down depending on a number of driving and driver variables.

A few being -

Driving habits?

Tire pressures?

Engine tuned up?

Lube & oil/filter changes (every 5,000-7,500 miles? Air filter changes (every 10,000-15,000 miles)? Read your auto manual for exact recommended intervals.

How many people in the SUV on average?

Are you towing anything?

Type gas you are burning - BRAND? (See injectors below)

Area you are driving in (hills and valleys verses flat out,
etc)

Jeeps in general don't have a good track record for great mileage, and rough engine idling is always a clue that your fuel injectors are dirty. Typical on all Jeeps with port fuel injection systems! On Jeeps with dirty fuel injectors your mileage will go way down accordingly. If your not putting at least a 12 oz bottle of say Walmart brand Super Tech Fuel Injector Cleaner (~ $1 each) in your gas tank religiously every logged 1000 miles, or every 2 tank fill ups, then you are just inviting dirty fuel injectors and POOR fuel economy!

My 1993 Ford XPLR with a 4L V-6 engine (and ~ 160,000 flawless driven miles) gets roughly 22 miles per gallon on the highway with cruise control on, and about 17 around town on average. I religiously put a 12 oz bottle of the above injector cleaner in my gas tank every 1000 miles!! Of course I do all my own tune-ups, general repairs, and suspension maintenance (shocks, O2 sensors, trans oil changes, lube & oil/filter changes, code reading and clearing, etc) myself and it shows! I don't trust repair shops except for say Tires and Balancing at SEARS.

Hope that helps ease your mind about gas mileage as it relates to your Jeep there.

Frank

Compare Fuel Estimates for 2006 Mitsubishi Raider Trucks Here's a comparison of EPA fuel economy ratings among the trucks in the 2006 Mitsubishi Raider lineup. As always, your mileage will very likely differ. 2006 Mitsubishi Raider 2WD 6-cylinder Trucks * 3.7L, 6-speed manual, 16 city / 22 highway * 3.7L, 4-speed automatic, 16 city / 22 highway * 3.7L, 6-speed manual, 16 city / 20 highway