I find my "winter" MPGs to drop to about 22-23MPG as well mainly because I let the car idle for 10 minutes or so in the morning to get the interior warmed up a bit. Premium won't do anything for the gas mileage, unless the car needs it. Very common belief...that isn't true.

 

Thanks for replies.
I'm in the northeast (NY state) so yes I warm the car up in the morning for 5-10 minutes. Don't turn heater fan higher than 1 until engin is at operating temp or I'm ready to drive. Normally that uses very little gas and I always 'thought' it was better for the engin and MPG to warm car up to operating temperature; warm the oil up (5w30)and get catalist up to temp and all that fun stuff.
Excessive idle time will reduce MPG, yes. Right now that Neon is burning more gas than my Blazer. Idle or drive.
I had the issue with the spark plug tubes leaking oil. I redid the tubes with 'indian head' gasket maker and replaced the spark plugs with Bosch platinum spark plugs so I wouldn't have to worry about the gap. Old plugs were only six months old Champion but after pulling, cleaning oil out of tubes... they got pretty fouled up.
Can't find any air leaks. Maybe it's the plugs... I can litterly watch my gas gage drop as I drive which is infuriating. I'll go through her again and check stuff but it's winter and not as fun. Car needs an overhaul.. when I did the spark plug tubes 4 of the rocker cover bolts were snapped and 2 were stripped out and the tubes were all bent like he used vice grips to pull the tubes out... and the base of the tubes were bent so he probly hammered them in there. Kid made an abortion of everything he touched. Gotta love it

 

Anytime the car is idling, you are getting 0 MPG. If you are all about MPGs, turn the car on, let it run for a few seconds to get the oil circulating and be gentle on the throttle for the next 10 minutes until the engine gets heated up real good.

Neons generally don't like Platinum plugs due to the type of ignition system (waste spark IIRC). Mine ran with them; many don't run very well.

 

If your premium gas comes WITHOUT ethanol, it does. I see a 2 mpg difference, enough to offset the higher cost, and I find that my oil is a bit less dark when I have gone a whole oil change cycle with ethanol free fuel. Not to mention, I have the AC on all the time, because it heats quicker, and defrosts so much better with it on.

 

What else did he destroy, or add to the car, that does not belong on it? This may be part of your problem. What about tire size? When I went to a taller tire 205/65/15 to 215/75/15 for better ground clearance on my G Voyager, I instantly noticed almost a 1.5 mpg drop on the overhead display, and a bit more sluggish, but I like the almost 1 inch gain in the front-keeps me from snagging the oil pan on jobsites. If you go to a smaller diameter tire that may help as well. Kick up the tire pressure a bit. When I go from my summer tires to snow tires, there is a bit more drag because of the softer tread and sidewall. Brakes dragging? Feel the wheels after a long drive, if they are hot, chances are you found part of the problem. Is it going into 4th gear?

 

I suppose if you can guarantee that your fuel of choice doesn't have ethanol in it, ANY octane will result in higher gas mileage. Higher octane has nothing to do with gas mileage. It's a knock rating. There is no law that requires gas stations to post a sign stating the fuel in fact does have ethanol in it, so it's also hard to say for sure on that fact alone.

 

Here's a site that tells you which gas stations in the U.S. and Canada have ethanol free gas. http://pure-gas.org/

 

Off hand, what else did he butcher... He installed a high amp stereo system which melted the wire harness. Brake lines... oh god. Instead of replacing the brake lines as a whole he cut out the leak and installed compression fittings. Rear passenger failed after first week. Front driver side after a month. The timing belt cover was smashed (not removed). The splash guard for under the engine and around the front passenger tire gone... I replaced splash guards with sheet metal flashing for now. He installed a huge spoiler on trunk and for cut away the trunk from the arms and installed pins to hold trunk arms... for some reason he needed the ability to remove trunk, maybe to install giant speakers for raves? Painted rear brake/tail lights 1"x2" visible light. Removed ALL fuel/brake line brackets and replaced with zip ties. 5" tack installed on dash. He did install an MSD coil pack.
Stripped/broken bolts on valve cover were a simple fix, just annoying. Did see a leak on passenger side near the firewall. He did try to drill a new hole rather then use "easy outs" but apparently got flustered because bolt was gone.

I looked at tire size. Number on door was (minimum tire size) read 165-80-13. Tires I installed are 185-65-14. I went to this site http://www.discounttire.com/dtcs/infoTireMath.dos according to the calculator there is only 2.75 revolutions per mile difference between the tires. Rim size is 1" larger but overall tire diameter is roughly the same. Rear tires are 185-75-14 but that's inconsequential. Have not changed tires since issue started. Used rims that came with car and guy at junk yard where I bought tires said that overall tire diameter is what mattered so he said he'd try to get that as close as possible. From the calculator, he apparently did a good job.
Normally check tire pressure about once a week and try to keep them in 40-45 PSI range. Have an issue with running over nails and stuff on job sites. I use the tire goop (green stuff). 1 cup per tire. Stuff works great... If I hear tapping while driving I just pull the nail out and the tire seals it'self. Way faster/simpler then plugging.

I do plan on installing a steal plates to protect the oil pan and another vital areas such as the fuel, brake and gas tank. Car does ride low, doesn't bottom out all too much but I did manage to scratch a whole in the gas tank.
I'll pick up some Champion 3344 plugs on the way home tonight and see if makes a difference. They were what were in the car before or just go with 344? In your experience what is the best spark plug for the 2.0 SOHC? Gap is .035 right? Don't care if it costs a little more for the spark plug because you can make up the difference on fuel consumed. Just want the car to run as well as possible.

$300 car has turned into a hobby but I like the car and it's fun to drive.

13.00 inner tie rod (passenger)
18.00 outer tie rod (passenger)
21.00 tie rod tool
49.00 O2 sensor
8.00 air filter
26.00 fuel filter
21.00 ball joint (passenger)
8.00 brake line 4' (driver/rear)
18.00 wire sleeve
6.00 heat shrink tubing
40.00 front wheel hub/bearing press in labor (passenger/front)
39.00 front wheel bearing (passenger/front)
20.00 wire harness
27.00 25' brake line
5.00 brake line end ... flared threaded nipples (4 pack)
23.00 flaring tool
8.00 break fluid
12.00 power steering fluid
22.00 MIG welder wire (frame/muffler repair)
58.00 wheel bearing (rear/passenger)
83.00 windshield
19.00 urethane (windshield install)
12.00 JB weld (gas tank/muffler repair)
5.00 hose clamps (gas line EVAP repair)
50.00 4 tires
14.00 antifreeze (flush/fill)
20.00 5 quarts oil
5.00 oil filter
13.00 head light bulb
13.00 left, front blinker/marker light socket
19.00 brake shoes
13.00 brake spring kit
22.00 valve cover gasket kit
12.00 antifreeze
5.00 engine oil 2 quarts
13.00 spark plugs (4)
35.00 spark plug tubes (4)
6.00 Indian head gasket maker
3.00 vacuum tubing (PCV)
learning about your car... priceless

 

I get around 25 every day. I use 87 octane and fill up about once a week. I can get ~300 miles out of a tank. I'm hoping to get better with my new CAI and replacement valve cover.

 

awesome, a station by the lake I hit up in the summer time I'll have to try a tank of that an see how it runs! Guess I been running the wrong gas in my boat too lol


I also went with bigger tires, 185/70/14 michelins. It's saved the a/c condenser, 2nd radiator, couple stock steel rims, 1 LF spindle, oil pan, trans pan. The way my daughter drives this thing this has been a pretty good fix as it had 55's when we got it lol talk about low ridin neon! Of ocurse the undercarriage plastic had all been ripped off by the previous person that owned it.