ight i had my neon for about a year, and this car is getting worse with the gas, it use to do over about 300+ to the tank now it only does about 200-250, and then on the city its even worse, and the car is running really weak, like even my toyota avalon 3.0V6 gets way better mpg on the neon i can do about 450 miles to the tank on the V6 and it sucks that the neon cant even do it, and i do change my plugs and oil and the filter and still nothing, i even add fuel injector cleaner and nothing, i havent checked my compression in a while but last time i remember it was uneven, around 140-150 psi, i know its a lil low, but still even on my toyota tercel before i did my swap i had 90psi on all cylinders, that does way more mpg and it can even beat the neon with my car burning oil like crazy, i like my neon but damn it sucks having to put gas all the time with these gas prices.

 

140-150 is fine. There are different ways to check the compression. It will vary between cars and how you do it. cranking test, snap test, and running compression. How many miles on the engine? You can also do a leakage test to see where the compression is going during the stroke. ALot of times on the sohc the rocker lobes go bad and actually push into the rocker when they go to push on the valve. Which will not open the valves as far. no cels? Sounds like a o2, or just needs a massive tune up.

 

Have you changed the air filter and PCV valve lately? Checked tire pressure? Had the alignment inspected?

There is so much that goes into MPG.

 

no CEL, my PCV changed, Alig is good, o2 i dont know if the last owner change which i guess it wasnt, air filter has been changed, i havent done the leak down test yet, but when i get a chance to have the cars in my hands ill do it, my girl drives the car to work, but even when i drive it still the same, and we both take it easy on the gas, i even clean out the T/B and few month ago i even did that emissions cleaning, by putting that liquid into the motor, and yes smoke came out, i did it my self the brand was Valvoline that i had from my old work, and they dont sell it at stores, spark plugs i usually change every 3 oil changes just to keep the MPG up with NGK spark plugs, even did the thermostat cause the last owner did not do it and almost burn the car up cause it over heated on me on a long trip, also would it be good to try doing synthetic? motor should have around 160-165K miles, and does not leak, only time when there is no oil is when i need to do my oil change, once my miles are done, the oil will slow go down on the dip stick, meaning i see less when i did my 3K miles

 

also i dont think that i mention that its also auto, and the tranny fluid is clean, does not smell burnt

 

you need to consider that most neons have a 9 gallon gas tank where other cars such as your avalon prolly have 12-19 gallon tanks. there for the extra distance you need to calculate your mileage based on how much you put in and how far you go with it....rather than how far you go.

 

ok if you want ill put my toyota tercel that had the same 10-11 gas tank same as the neon or the neon is bigger, ok my tercel had a **** load of mods such as stage one cam, high flow cat, 4inch exhaust tip, fully rebuilt head, bigger T/B short ram intake, and having to put a quart of oil every two days because piston rings was shot to death and still doing more MPG than the neon, i did with that car about 325 miles to the tank and the crank seals was going away.

ok i did my compression test on my neon what i got was 165-165-210 because oil fell in the cylinder due to valve cover gasket and the last one was 170, i pour oil in all cylinders and it went to 205-210-210-205, its weird it kept giving me diff numbers, but still yes a toyota avalon with a bigger motor and more horse power with a 15gallon tank should suck more gas than a 4cylinder, but still its sad that the neon is just crappy on gas and i take care of my neon, i dont rev high on it cause its auto, sounds like **** but i like driving it and every thing is stock, and i rented a hyundai and it was even fast than the neon, and my tercel when it was stock only had 82HP still beat the dodge neon and i beat the **** out of my tercel, but i like my neon and i want to improve the MPG on it.

also no one answer this but would it be bad to put synthetic on the neon? i would put new o2 sensor but they are really pricy

 

No neon came with a 9 gallon tank. 12.5 gallon tank for years '96-'99 (plastic) and 11.7 gallon for the '95 year (metal).