98 accord mpg

[russianhomi]

I know this question has been asked a million times but here it goes. I have a 98 accord I4. My mpg's for the past 4 years have been roughly 28-31 highway and 24-26 city. About two months ago they changed to being 23-24 highway and 19-21 city. This happened almost in a blink of an eye. Here is what I have checked and or replaced.
spark plugs brand new ngk iridiums, plug wires, cap and rotor brand new.
Air filter has less than 5k on it. Tire pressure is 35 all around with no balance or allignment issues. I have run seafoam through the system along with techron injector cleaner multiple times in the past. I replaced both 02 sensors after getting a cel. The only thing I am suspicious about involves my rims. I went froms stock 15's to 18s HOWEVER my total diameter is the same because i got lower profile tires. The stock 15's were very thick rims and weighed as much if not more than these new ones so I doubt that weight is a problem. I have run out of ideas. I drive the car the same and just as a test i drove it like a grandma staying under 3k rpms for an entire tank with the same 21 mpg result. I have heard of this "winter blend" of gas yielding less mpg but in 5 years of owning this car the mpg's have never even come close to what they are now. Any ideas on what could be the problem? Thanks in advance

[redaccordcoupe]

are your rims pushing way wider than stock tires?

[nehonda]

If you still have your old 15" rims and tires, put them back on for a while and see if the mileage goes back to where it was. Maybe the new tires have more rolling resistance??

[redaccordcoupe]

Originally Posted by nehonda

If you still have your old 15" rims and tires, put them back on for a while and see if the mileage goes back to where it was. Maybe the new tires have more rolling resistance??

or the wheels are just heavier all around.

[russianhomi]

Yes the overall width is slightly more. I will try the stock rims for a tank or two and see what happens. If that doesnt fix it, I don't know what will. I'll post back soon.

[Jecht]

Also remember about two months ago gas stations switched to winter mix gas and that can drop MPG

[AccordNV]

I wonder if that mix is what happened to me. Last tank I had my best ever hitting 525 miles for the tank, and so far on this one I'm only at 125 and just over half a tank left. I usually get around 400 to the tank

[russianhomi]

same here! My arrow stays put for the first 30 miles then goes down very quickly to just above halfway and by halfway I am at 165. Then it only speeds up for the second half. I remember the days when I could easily get 240 miles at the halfway mark on the highway. Now I just drove all highway and barely broke 190. I would think that if this winter gas mix took such a toll on mpg's then more people would recognize the problem.

[stiller fan]

since you switched rim sizes, it could be a couple of things....

1. you did not re-calibrate the speedometer/odometer for the larger circumference of the rims....

2. more torque is needed to start rims turning, hence lower MPG's...

i could be wrong here....

[redaccordcoupe]

Originally Posted by stiller fan

since you switched rim sizes, it could be a couple of things....

1. you did not re-calibrate the speedometer/odometer for the larger circumference of the rims....

2. more torque is needed to start rims turning, hence lower MPG's...

i could be wrong here....

i beleive it to be those two things on top of the winter garbage fuel

[stiller fan]

very well could be.....

[russianhomi]

I go to this quiktrip gas station and I've always measered the distance from one particular pump to the garage door in my driveway. With my old rims I would get just past 2.3 miles Literally it would go from 2.2 to 2.3 in my driveway. Well unfortunately it is the same with the new rims. I dont think recalibration is needed. The rims have been on the car for almost a year. If my memory serves me correctly, my mpg's were fine when I installed them.

[stiller fan]

Originally Posted by russianhomi

I know this question has been asked a million times but here it goes. I have a 98 accord I4. My mpg's for the past 4 years have been roughly 28-31 highway and 24-26 city. About two months ago they changed to being 23-24 highway and 19-21 city. This happened almost in a blink of an eye. Here is what I have checked and or replaced.
spark plugs brand new ngk iridiums, plug wires, cap and rotor brand new.
Air filter has less than 5k on it. Tire pressure is 35 all around with no balance or allignment issues. I have run seafoam through the system along with techron injector cleaner multiple times in the past. I replaced both 02 sensors after getting a cel. The only thing I am suspicious about involves my rims. I went froms stock 15's to 18s HOWEVER my total diameter is the same because i got lower profile tires. The stock 15's were very thick rims and weighed as much if not more than these new ones so I doubt that weight is a problem. I have run out of ideas. I drive the car the same and just as a test i drove it like a grandma staying under 3k rpms for an entire tank with the same 21 mpg result. I have heard of this "winter blend" of gas yielding less mpg but in 5 years of owning this car the mpg's have never even come close to what they are now. Any ideas on what could be the problem? Thanks in advance

'

hmmm, have you checked for a bad fuel injector? could be leaky....

[russianhomi]

I am planning on taking out the fuel rail and checking/replacing the injectors... just not when its 16 degrees outside.

[russianhomi]

One more very suspicious thing I found was the new updated mpg figures from the epa. They dropped the highway/city mpg figures on almost every car. If you check the I4 accord, the new figures are 20/27. Thats insane for a I4. I just love the excuses for this, such as more stop and go traffic and more air conditioning. As if we never used the AC before. My first instinct is that something has been done with gasoline along the lines of diluting. I know this is a conspiracy theory but my mileage drops like crazy and suddenly there are new mpg figures... Ive called 4 shops who had no idea what my issue could be. This is just the thought but check your vehicle on this site and see what the "new figures" are.

http://www.fueleconomy.gov/feg/findacar.htm