My brother owns a 2000 Neon and is having serious problems with fuel economy lately. He is now getting only 200 or so miles per tank.

I thought I would search here, but I couldn't find anything.

There are no DTCs in the computer.

Do Neons have any history of this kind of behaviour? Maybe an O2 sensor that's failed without tripping a DTC?

Any ideas?

Thanks,
Mark

 

well...all i can tell you is that neons lose their good fuel economy pretty fast i guess. I actually haven't ever tested mine. I do know it seems like it changes...my driving is pretty consistent though. A lot of people on these forums are only getting just above 20mpg i believe. I can't tell you why though.

Seafoam helps but your mileage is back to crap after like a week or two. I did it to mine and it was great but it was back to how it was running before in about a week.

 

My economy jumped a bit up when I changed out the filter to a K&N. I have a bit of mods that don't help the mpg...especially the 60mm tb, but I think a lot of it is the gearing of the ATX's.

I am probably only going to get like 20-22mpg this tank but that's because i ran it hard...did a lot of stupid wot runs and stuff.

 

i average 220-240 miles on a full tank. I believe that is just above 20mpg, there is nothing wrong with my car as we speak (knock on wood), i think that is pretty much what several neon owners get as far as mpg is concerned. O ya and my driving is about 95% city, which may have somethin to do with it

 

He makes it sound like it was a pretty rapid change. From consistantly getting 250-260 miles per tank to suddenly getting 190-200 miles per tank.

I didn't think Neons were that bad! His is a 5 spd, I should add.

 

Sometimes it can be the fuel you use. Winter mixes are different from Summer ones, that might have something to do with it. Also, check the air cleaner and cat. A pluged cat will make your mileage take a dump as will a dirty air filter. Also, if he's not already done it get rid of the resenator and just use a short piece of tubing(I used a Dickie's BBQ cup with the bottom cut off, fit perfectly) to stick into the fender well. That'll bring more cold air into the air box and with the addition of a K&N you'll have a low budget CIA of sorts and you won't have such a pain changing out the filter like the CIA's with the filter in the fender. Good luck, hope ya' get it sorted out.

 

its not that our neons are that bad, just our gas tanks are smaller

 

check the pressure on the tires, air filter, maybe change the sparks, and dotn step on the gas like a crazyass kid

 

All the basic suggestions are already done. Tire pressures, air filter, fuel filter (I think he said he did this one), etc.

How would one go about checking for a plugged cat?

He's had the car for several years, and is now suddenly noticing the drastic drop in fuel economy. He's repeated the results on several tanks of gas. I highly doubt the root cause is a lead foot. It's not like he's changed his driving habits in the last 4-5 tanks of gas.

 

You get a tube to replace the cat and run the car for a while to see if things improve. If they do then the cat is bad and you get a free flowing one(might as well upgrade, why go back to stock) and install it. Like I said, a lot of people get poor mileage because of the Winter blended gas. Do a google on it and you'll see. Hope you figure it out, with gas at $3 bucks a gal. it sucks to not get all the mpg you can.