I have a 2003 Doge Neon SXT with automatic transmission. I was wondering what went wrong on my car because I was getting a very bad mieage. It has 53k which is a pretty new car. I recently just got the oil and oil filter changed. However, a full tank(which is about 10 gallon I think) can only run like 160miles, which is 16mpg.

I drive to class sometimes and because the college is just like 5min away so I always have a cold start(I hope that's the right word to explain I get the car running before the engine warmed up). I thought the MPG rating for auto trans is suppose to be at least 25. I'm getting only about 16mpg which makes me very unhappy and worry about it.

I just bought this car like 2 months ago and I believe that the previous owner have never changed the spark plug before. I am going to find a mechanic shop to change it but I don't think that's the only reason this car is getting the bad MPG. I don't have that kind of bad driving habit that do a lot of rapid acceleration so I really need to find out the reason behind.

Can somebody throw in their two cents about how I should fix it and also tell me your MPG to compare.

Also... what is the reasonable labor cost of changing spark plug. I asked a shop before and they quote me $50 for that and they are selling $6.50 each for a copper resistor plug.
With tax, that would be around 85 bucks. Does it sound reasonable?

Thanks for answering my questions. I am just a beginner in car that needs help = )

 

you might be getting worse mileage. The tank is 12.5 gallons, and you getting only 160 miles equals to 12.8 mpg. sounds like you need a tune up. plugs and wires should be done. plugs are cheap, $1.76 for one, and wires for 25 bucks. if you know how to turn a wrench you should be able to do this yourself no problem.

 

This is something that anyone can do themselves with very little basic automotive skills. The total cost of replacing 4 copper core spark plugs yourself will be less than $10.

You will need a 3/8" ratchet, a 6" ratchet extension, a 5/8" spark plug socket, a set of gap gauges, and four Champion RC9YC spark plugs. Don't let the parts guy sell you anything else.

Open the hood and look at the top of the engine (valve cover). There are four wires running to four locations on the top of the valve cover. These are the spark plug wires.

Grab the one on the left at it's base (the boot) and give a firm pull, not a jerk, while twisting the wire back and forth gently until you feel the wire come free of it's hold on the spark plug.

The boot is about 4" long and will pull completely out of it's hole. Now you can see the end of the spark plug.

With the spark plug socket on the end of the ratchet extension put it down the hole and over the end of the spark plug. Twist back and forth to make sure that the socket seats completely to the base of the spark plug.

Now put the ratchet on the extension and swing the ratchet handle to the right from an 8 o'clock position which turns the spark plug to the left. There will be quite a bit of force needed to "break loose" the spark plug if these are the original spark plugs so be careful to stay straight on the spark plug while doing this step. Once broken free unscrew the plug from the hole.

Now get a new plug and your gap gauges. Select the .035 gauge and place it in the gap on the end of the spark plug between the center and outer electrodes. Too big?

There will be a slotted tang on the set of gauges that you will use to adjust the gap by bending the outer (curved electrode) on the plug. Be careful not to contact the white ceramic part of the center electrode as it is very fragile and will chip easily while bending the outer electrode. It bends easily so be gentle and check the gap when you think you have it bent enough.

The gauge should slip into the gap with just a touch of friction. That's perfect. If you've gone too far just bend it back a little. When you achieve the correct gap load the new plug into the socket with just the extension attached.

Now lower the plug, socket and extension back into the hole and after you have reached bottom feel for the center of the hole. Once you have found the center of the hole begin turning the extension, socket and plug to the right BY HAND ONLY until you can no longer turn it.



Now get your ratchet and turn the extension, socket and plug an additional 1/4 to 1/2 turn to the right. Put the boot back down the hole over the end of the new spark plug and push. You should hear a small click as the wire clips itself to the end of the plug. You've just changed a spark plug!

Now that you're an old pro there are 3 more to go. Just do one at a time till you're done.

While you're at it that thing with the hose attached that sticks into the right hand end of the valve cover is the PCV valve. Pull the hose off and unscrew it (left) and put a new one in. Your Neon will thank you for it along with that NEW AIR FILTER you're going to put inside that black box in front of the battery. Isn't car care fun!

My wife's 02 Neon routinely gets 28-33 mpg but it is always well maintained.

Learn some skills son and save yourself a lot of money by doing things yourself.

 

Thanks for both of your tips.

Thanks deranged a lot for teaching me how to change spark plug by myself but I'm only an international student and probably not going to use the tool more than once because I will graduate before I have to change the spark plug for another time.
So, it would not be feasible to buy tools and work on it myself I think.

How much does it cost normally for a tune-up?
Is there any other reason that is causing the low MPG?
Do the wires and plugs account a big part of getting low MPG?

Thanks again, guys.

 

-My Wife's '05 Neon only gets around 23 MPG or so with in town/city driving. But I just filled her car tonight and with the highway driving she does to work and back, it hit 36 MPG. When we've gone on vacations, it topped out at 37.5 for us. But like I said, city mileage sucks. But you sure do sound like you need a tune up. Another thing you can do at least get a bottle of Seafoam fuel cleaner and put that in the tank. You might have some pretty dirty injectors causing part your problem.

L8R,
Matt

 

Does the fuel cleaner really work? I just did some research online and some said it worked and some said it would harm the engine performance and parts.

Also, what would a tune-up generally cost? and what services would it include?

 

Didn't you post something very similar to this a few months ago? I take it you never got anything on that list you asked me to PM you done?

 

Your car is not really old enough nor does it have the miles on it to need plug wires yet. Plugs, PCV valve and air filter have a lot to do with gas mileage along with proper tire inflation. This is a 4 cylinder engine and any little thing being off will greatly affect performance. It only has those 4 cylinders to make power and if everything is not up to snuff your foot goes farther to the floor to make up the difference in power. More gas = less miles per gallon. I'd still suggest buying even some cheapy tools or borrowing some and doing it yourself. Something you'll be able to refer back to when you do it on your next car and you'll still end up doing it for less than the $85. Maybe $30-$35 at most. JMO

 

Actually it is not all that similar. I was asking for things like maintenance and recently I just found out that I have some unbearable mpg.

I got my oil changed, tires rotated and air filter changed thanks to you.

Thanks again for the info. I will try to get it done.

 

I was asking because maintaining the car will ensure good gas mileage the whole time. Good to hear you got some of it going though!