OK here is what I have
1998 Dodge Neon Highline Sport DOHC ATX
I get from 12-18MPG in the city and about 20 on the highway. Is this normal or is my car crazy? What can I do about this.
This tank I got 150 miles in the city from Full to Empty. Something is not right
Engine is COMPLETELY STOCK. Only mods are window tints, and a sound system.

I get from 12-18MPG in the city and about 20 on the highway. Is this normal or is my car crazy? What can I do about this.http://forums.neons.org/images/smiles/icon_eek.gifhttp://forums.neons.org/images/smiles/icon_eek.gifhttp://forums.neons.org/images/smiles/icon_eek.gif
You can do the simple tune up things: Change spark plugs (w/stock Champion copper ones), New PCV valve, new air filter, fuel filter, clean your throttle body, check tire pressure, run some fuel injector cleaner at your next fill up. This should help you, if not, then you may have an engine problem. Post back with any findings and I will see if I can help you out further.

http://forums.neons.org/images/smiles/icon_eek.gifhttp://forums.neons.org/images/smiles/icon_eek.gifhttp://forums.neons.org/images/smiles/icon_eek.gif
You can do the simple tune up things: Change spark plugs (w/stock Champion copper ones), New PCV valve, new air filter, fuel filter, clean your throttle body, check tire pressure, run some fuel injector cleaner at your next fill up. This should help you, if not, then you may have an engine problem. Post back with any findings and I will see if I can help you out further.
Ive done the injector cleaner and nothing. Tire pressure is 32. Whats a PCV Valve? Im gona get a K&N air filter, fuel filter plugs nad wires will be done at tuneup.

Ive done the injector cleaner and nothing. Tire pressure is 32. Whats a PCV Valve? Im gona get a K&N air filter, fuel filter plugs nad wires will be done at tuneup.Positive Crankcase Ventilation valve. They are like $3-$5, a cheap replacement and a world of difference. The K&N filter is a good idea, but you don't need a brand name one, unless thats the way you want to go.

Positive Crankcase Ventilation valve. They are like $3-$5, a cheap replacement and a world of difference. The K&N filter is a good idea, but you don't need a brand name one, unless thats the way you want to go.
And where do I install this PCV? K&N I heard adds a few horses along with a few MPG. But I dont understand I just had a Fram put in at 62.6k miles and its now 66.5

And where do I install this PCV? K&N I heard adds a few horses along with a few MPG. But I dont understand I just had a Fram put in at 62.6k miles and its now 66.5Your PCV valve is on the backside of the valve cover.

Well I just found out I ned premium in my car. Doing that it runs smoother, but I havent kept track of the milage yet. I found out that for all of the miles that were on the car up to this point, the previous owner used regular in it. Can this be the cause of things? Just a worn out engine?

Well I just found out I ned premium in my car. Doing that it runs smoother, but I havent kept track of the milage yet. I found out that for all of the miles that were on the car up to this point, the previous owner used regular in it. Can this be the cause of things? Just a worn out engine?

Not likely. is there a check engine light on?

Well I just found out I ned premium in my car. Doing that it runs smoother, but I havent kept track of the milage yet. I found out that for all of the miles that were on the car up to this point, the previous owner used regular in it. Can this be the cause of things? Just a worn out engine?I doubt running regular would cause the engine to just be worn out. How many miles are on your car? If the engine/car was not taken care of properly or driven hard, you may experience the loss in gas mileage.

I doubt running regular would cause the engine to just be worn out. How many miles are on your car? If the engine/car was not taken care of properly or driven hard, you may experience the loss in gas mileage.
67k miles. I got it when it had 62.5 the milage was like that from the start, and i drove it hard as well.

OK here is what I have
1998 Dodge Neon Highline Sport DOHC ATX
I get from 12-18MPG in the city and about 20 on the highway. Is this normal or is my car crazy? What can I do about this.
This tank I got 150 miles in the city from Full to Empty. Something is not right
Engine is COMPLETELY STOCK. Only mods are window tints, and a sound system.
I have the exact same car (is yours green?).

Anyway, last winter, I was getting about 200 miles before the gas gauge reached the 3/4 mark. this is about equivelant to 24 MPG. Then last may, I got a check engine light for an engine misfire. I had to get the car inspected, so I replaced all the wires, changed the oil with 20W50, new filters all around. To get the check engine light to turn off, I had a friend reset the computer.

All summer, the MPG was 160 miles to the 3/4 mark (about 20MPG). Since I also own a VOyager Minivan that was getting 19MPG, I knew something wasn't right. At first I blamed it on resetting the computer, and it needing to "re-learn" my driving habits. Then I blamed using the AC. In September, I changed the oil to 10W30, because I couldn't find 10W40. My Mileage went back up to 24-26 on the next fill up!

I have owned a series of high milage Honda Accords over the past 20 years (my Vanity tag was "HONDENT"). It seems my policy of using 20W50 in the summer, 10W40 in the winter, doesn't work well with MOPAR vehicles. I am really surprised it makes such a differance.

In September, I changed the oil to 10W30, because I couldn't find 10W40. My Mileage went back up to 24-26 on the next fill up!An SAE 40 oil is a bit thick for our little 4 cyl neon. 5W30 is what I put in and get around 26-30 mpg in the city driving in an ATX.

An SAE 40 oil is a bit thick for our little 4 cyl neon. 5W30 is what I put in and get around 26-30 mpg in the city driving in an ATX.

Yeah... and I was using 20W50 all summer. using 20W50 made no differance in the MPG in my "Hondent" 2.0 liter, but then the Hondent engine is a shorter throw / Higher reving design. Problably differant rings too. I use 20W50 in My Honda Motorcyle in the summer too.

I have the exact same car (is yours green?).

Anyway, last winter, I was getting about 200 miles before the gas gauge reached the 3/4 mark. this is about equivelant to 24 MPG. Then last may, I got a check engine light for an engine misfire. I had to get the car inspected, so I replaced all the wires, changed the oil with 20W50, new filters all around. To get the check engine light to turn off, I had a friend reset the computer.

All summer, the MPG was 160 miles to the 3/4 mark (about 20MPG). Since I also own a VOyager Minivan that was getting 19MPG, I knew something wasn't right. At first I blamed it on resetting the computer, and it needing to "re-learn" my driving habits. Then I blamed using the AC. In September, I changed the oil to 10W30, because I couldn't find 10W40. My Mileage went back up to 24-26 on the next fill up!

I have owned a series of high milage Honda Accords over the past 20 years (my Vanity tag was "HONDENT"). It seems my policy of using 20W50 in the summer, 10W40 in the winter, doesn't work well with MOPAR vehicles. I am really surprised it makes such a differance.
Yea its green. Where do yuo live? Also, instea of using 5w-30 like he was supposed to, my grandpa stupidly filled it with 10W-40. But even before the oil change, the milage was pretty bad. I just dont know what to do. There is no check engine light on, but then again if im not buckled in, there is no light either. Its a nice car, but sometihng in screwed. I cant even keep up track-wise with my frineds 98 Altima GXE AUTO stock.

what about the O2 sensor? its not a bad idea to replace those 50-60k especially if youre noticing things like mpg drops and whatnot.

what about the O2 sensor? its not a bad idea to replace those 50-60k especially if youre noticing things like mpg drops and whatnot.
Wouldnt a faulty sensor cause the service light to trip? My mechanic said it switches 5 or 6 times in 10 seconds nad if not, the light comes on.

O2 sensors can get lazy and not set a light but can affect gas mileage. ive seen it on a lot of vehicles. its not that hard to replace and you should notice an improvement fairly quickly.

what about the O2 sensor? its not a bad idea to replace those 50-60k especially if youre noticing things like mpg drops and whatnot.It's not a bad idea, but if you aren't getting codes for them, then I would leave them be, personally! If you are noticing your MPG dropping, try changing your spark plugs (no platinum plugs), PCV valve, air filter, and maybe the fuel filter.

It's not a bad idea, but if you aren't getting codes for them, then I would leave them be, personally! If you are noticing your MPG dropping, try changing your spark plugs (no platinum plugs), PCV valve, air filter, and maybe the fuel filter.
I didnt connect it to a computer yet, but I will sometime this week. I changed the spark plugs, but notihng. The old ones had oil all over them, and someone said it might be the valve cover gasket going bad. Can this cause bad milage? I changed the air filter when I got the car. It currently has a FRAM with the stock air box, and it has 4-5k miles on it. The new spakr plugs have under 500 miles on them. I asked my mechanic about the PCV and he said it doesnt affect gas milage. Fuel filter, I am thinking about but I dont know how much it will cost.

I changed the spark plugs, but notihng. The old ones had oil all over them, and someone said it might be the valve cover gasket going bad. Can this cause bad milage?Your spark plug seals need to be changed. But in order to that you have to pull off the valve cover, so you have to replace that seal also. Oil in the spark plugs will cause the plug not to function corectly affecting gas mileage.

I asked my mechanic about the PCV and he said it doesnt affect gas milage.The Positive Crankcase Ventilation valve is an emissions control device that routes unburned crankcase blowby gases back into the intake manifold where they can be reburned. The PCV system is one of the oldest emission control devices, and also one of the most beneficial. Besides totally eliminating crankcase emissions as a source of air pollution, the constant recirculation of air through the crankcase helps remove moisture which otherwise would cause sludge to form. Thus the PCV valve extends the life of the oil and engine. The PCV valve requires little maintenance.It's just good maintenance!

Yea its green. Where do yuo live?


I am in the subeubs north of Philly. The Neon was my Wifes car, and she bought it in Wilmington DE before we were married. I got it when my 4th "HONDENT" Accord wouldn't pass inspection last year. We bought a minivan, and I drive more so I got the neon. I miss driving stick, but I have never had a sunroof before. Except for the engine + exhaust noise, I really find it fun to drive.

I really find it fun to drive.Get an MTX neon and you will experience some real fun! People underestimate this little car.

I am in the subeubs north of Philly. The Neon was my Wifes car, and she bought it in Wilmington DE before we were married. I got it when my 4th "HONDENT" Accord wouldn't pass inspection last year. We bought a minivan, and I drive more so I got the neon. I miss driving stick, but I have never had a sunroof before. Except for the engine + exhaust noise, I really find it fun to drive.
Where in the suburbs? Do you have stickers on your hood and a dent on your rear left quarterpanel? We should meet sometime and take pictures. Is yours auto? Can I pay you to teach me to drive stick?

there is a gray area for O2 sensors where theyre not operating as good as they should but they arent setting a light. its like 40$ and not overly hard to change.

there is a gray area for O2 sensors where theyre not operating as good as they should but they arent setting a light. its like 40$ and not overly hard to change.
I have a haynes manual so I can change them myself. How much is the part. And what grey area?

i used that word to describe a situation where there is a sensor that operates well enough that the computer wont set a light but its not working as good as it should.

i used that word to describe a situation where there is a sensor that operates well enough that the computer wont set a light but its not working as good as it should.
AA i see. How much is the part? Cause I know there are 2 sensors

you should only change the one closest to the engine. as for prices you would have to check with the parts store. make sure you see how many wires the sensor has, what the connector looks like and how long the wires are. you can get the right box but wrong sensor and having that info will keep you from making multiple trips ;). anyway i would expect the sensor to be about 40$ or so.

you should only change the one closest to the engine.That would be the upstream sensor and will run anywhere from $30-$60.

i was just trying not to confuse him by saying upstream, closest to the engine usually dispells any doubt ;)

I thought the I had the same problem with my Neon too. I got 193 miles on the trip meter and was near empty. Went to the pump and filled up with 5.5 gallons. Thats 35 MPG. So the gas mileage is right on the money, it may be your float in the tank or the gas guage itself. Need to replace the float (sending unit) or the instrument cluster.

well when i go to the pump nad have 180 miles on the trip and fill 9 gallons, then sometihng is wrong. maybe the trip is off nad i should watch the regular odometer instead.

well when i go to the pump nad have 180 miles on the trip and fill 9 gallons, then sometihng is wrong. maybe the trip is off nad i should watch the regular odometer instead.You should have a 11-12 gallon gas tank.

I would get someone to plug in a diagnostic and make sure its not throwing any codes to be sure.

I would get someone to plug in a diagnostic and make sure its not throwing any codes to be sure.
But there is no service engine light on. then again if im not buckled in, theres no light either.

when you first turn on your car, when all the idiot lights come on. do you see the check engine one? if its not there the light may be burnt out and there would be no way to know if it was throwing a code with out pluging it in.

when you first turn on your car, when all the idiot lights come on. do you see the check engine one? if its not there the light may be burnt out and there would be no way to know if it was throwing a code with out pluging it in.GREAT POINT!!!

when you first turn on your car, when all the idiot lights come on. do you see the check engine one? if its not there the light may be burnt out and there would be no way to know if it was throwing a code with out pluging it in.
Nop, its on. But no other dash lights work. The seatbelt thing. Only things that work are the guages and turn signals and odometer. But the seatbelt light works with the car not started.

Only other thing I can think of is that you have a gas leak in the fuel line somewhere behind the driver seat of the car and thats why you may not smell it, and it only leaks when it is running. Just a thought.

Might be on to something with the fuel leak. I've also heard of the intake manifolds cracking that would also cause poor gas milage. The MAF could be acting up too but still sending signal to ECU so no code.

The MAF could be acting up too but still sending signal to ECU so no code.The neon does not have a MAF sensor :shakehead

My bad. I'm just throwing things out there. I've never had to work on one extensivly.

Well I went to 3 different mechanics that didnt even know who I was and they looked at it and said it should be getting 17-18 city and 24-26 highway, so thats basically right what im getting. I didnt even tell them anything just asked what kinda milage it should get. They said if I want a gas efficient car, learn to drive stick, and get a civic or corolla.

My 98 Dodge Grand Caravan gets 20 to 23 mpg highway, there is noway that what the mechanic said could be right. Except for the manual transmission. And my 96 Neon is getting 30 to 34 mpg highway. I think you should still be looking for an answer to this whole thing. Since your car is getting what my van is on the highway. Enless you sport package is a six cylinder then we all have wasted our time on this post in the first place.

My 98 Dodge Grand Caravan gets 20 to 23 mpg highway, there is noway that what the mechanic said could be right. Except for the manual transmission. And my 96 Neon is getting 30 to 34 mpg highway. I think you should still be looking for an answer to this whole thing. Since your car is getting what my van is on the highway. Enless you sport package is a six cylinder then we all have wasted our time on this post in the first place.
At this point ive kinda given up hope.

At this point ive kinda given up hope.Try running some Seafoam throught your engine. It cleans soot out of your engine. Follow the directions carefully. It's cheap and may help you out.

Try running some Seafoam throught your engine. It cleans soot out of your engine. Follow the directions carefully. It's cheap and may help you out.
Tried it. Il just use synthetic oil and do regular maintenance. that should at least keep it in good shape till I save for a Jetta or SRT-4

Tried it. Il just use synthetic oil and do regular maintenance. that should at least keep it in good shape till I save for a Jetta or SRT-4Well damn! You checked for a cracked exhaust manifold right?

Well damn! You checked for a cracked exhaust manifold right?
nop

If it makes more sense for you all, its a HIGHLINE sport. Maybe because its heavier.

If it makes more sense for you all, its a HIGHLINE sport. Maybe because its heavier.Check for a crack in the exhaust manifold. Mine is also a sport w/all available options and my MPG aren't that low.

Check for a crack in the exhaust manifold. Mine is also a sport w/all available options and my MPG aren't that low.
Automatic? How many city miles do yuo get for 1/2 of the tank

Automatic? How many city miles do yuo get for 1/2 of the tankAnywhere from 125-150 miles. On a full tank I get about 250-270 miles. That is mostly city driving, on the freeway, I get 280-310 miles.

Anywhere from 125-150 miles. On a full tank I get about 250-270 miles. That is mostly city driving, on the freeway, I get 280-310 miles.I have 96 Neon Highline 5 speed 4 cylinder. The last full tank i went 322 miles and still had 1 gallon in the tank. I think thats great compared to the Grand Caravan. I drive all highway to work and back 27 miles one way.

Still think this is a plug issue.

PCV valve will cause idle issues but won't reduce fuel consumption enough to consider it an issue.

Also, cleaning the EGR valve might help. If it isn't allowing enough EGR gas through, detonation could be happening and the knock sensors will retard the timing.

Still think this is a plug issue.

PCV valve will cause idle issues but won't reduce fuel consumption enough to consider it an issue.

Also, cleaning the EGR valve might help. If it isn't allowing enough EGR gas through, detonation could be happening and the knock sensors will retard the timing.
Plugs were changed some 1k miles ago. The old ones were in bad shape and had oil all over the electrode end.

wet oil is from the thread and plug coming out through oil trapped in the spark plug tube.

wet oil is from the thread and plug coming out through oil trapped in the spark plug tube.
:banghead:What? :banghead: I am clueless.

When the sparkplug tube seals leak, they leak oil into the sparkplug tubes.

When you remove the plugs you will be pulling the plugs through that trapped oil in there.

That is why they were wet with oil.

If you were burning oil, you would have blue smoke out the tailpipe.

When the sparkplug tube seals leak, they leak oil into the sparkplug tubes.

When you remove the plugs you will be pulling the plugs through that trapped oil in there.

That is why they were wet with oil.

If you were burning oil, you would have blue smoke out the tailpipe.

I had a 1980 Toyota Corolla with the same set up with the spark plugs, what a pain in the ass. I think it is the worst idea they had.

Realistically it is harmless unless they are leaked badly. Seeing the spark plug is sealing the hole, no oil is getting into the combustion chamber.

Easy to replace the tube seals though and at the same time replace the valve cover gasket.