Gas milage gone wrong

[Ilovemyneon]

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.

[das2123]

Originally Posted by Ilovemyneon

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.

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.

[Ilovemyneon]

Originally Posted by das2123

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.

[das2123]

Originally Posted by Ilovemyneon

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.

[Ilovemyneon]

Originally Posted by das2123

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

[das2123]

Originally Posted by Ilovemyneon

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

Your PCV valve is on the backside of the valve cover.

[Ilovemyneon]

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?

[maykelcj]

Originally Posted by Ilovemyneon

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?

[das2123]

Originally Posted by Ilovemyneon

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.

[Ilovemyneon]

Originally Posted by das2123

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.

[gromittoo]

Originally Posted by Ilovemyneon

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.

[das2123]

Originally Posted by gromittoo

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.

[gromittoo]

Originally Posted by das2123

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.

[Ilovemyneon]

Originally Posted by gromittoo

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.

[RahX]

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.