I just bought an 04 tsx a couple of months ago and i feel like im getting really bad gas mileage. A full tank gives me 320KM(note not miles as im in Canada) before the light comes on. I do only city driving, no highway driving at all. Is this considered normal? I pump 91 octane as well. My car has almost 160,000km on it. What are some things that i should be looking at to improve gas mileage?

 

only city driving does that. try taking it on a longer highway (freeway) drive after a fill-up and check it out

 

That sounds normal if you drive short distances or heavy traffic. Basically that's what I get -driving 1 mile to work, and back, and other short trips-. But when I drive long distances, I can do over 630kms with one tank. In other words, I get 18mpg or less city driving and 34mpg highway

 

In the right (or wrong) conditions, the TSX can get only 14-16 mpg in city driving. I think we will need more details about your driving habits to determine the factors of the low mileage:

- how far do you drive (does the car have time to warm up or get past 35 mph)
- how cold has it been
- Park outside or in a heated garage
- do you let the car warm up before driving
- any mods on the car
- kept up with routine service
- does your local gas station use a winter blend fuel
- 5AT or 6MT
- driving habits: love the sound of i-Vtec all the time
- have you tested your electrical system (battery, alternator), could be adding more drain to engine

 

The car is a 5AT. I always let my car warm up before i take it out. It is parked outside in the daytime and in a private garage overnight. The car has no mods at all. I rarely hit vtec. I drive about 50km a day, city driving.

 

That seems maybe a touch low but with your drive characteristics, it is probably fairly normal. Extreme temp (high and low) and short distance will kill your mileage. If you get a run a tank with predominantly highway miles and you don't get close to upper 20s or better, you may need to have a mechanic look at it.

Some of the normal things to check are the air filter and intake throttle body. If these get dirty, they can affect mileage. Also check your tire pressure - less pressure can result in better handling but take a toll on your mileage.

 

Warming the car up is eating gas for little benefit. Idling gets 0 MPG. If it is really cold out, a block heater should have been used, otherwise, starting and waiting no more than 15-20 seconds is fine. Just avoid working the engine hard until it warms up.

 

Forgot to add, what type of tires. Sometimes winter tires can add more rolling resistance on roadways with no snow.

I think I would wait until it warmed up outside to +40F (+5C) to see if things improve mpg wise.

 

The first thing you should check is whether or not a tune-up has been done. Change the spark plugs with the oem iridium plugs and air filter. Second, check to make sure the alignment is ok and tires are the correct psi.

Also, city driving WILL give you a lot worst gas mileage, even with the four cylinder in a TSX.

 

Well you guys Must remember that everything is a factor.
I highly suggest a few steps
1. New Car and Spark Plugs: They may have put on brand new spark plugs, but that really does not mean crap if they are not high quality.
My first set of advice for way better gas mileage is invest in some quality and premium NGK Laser Irradium plugs. Automatically a boost in MPG, and also lower emissions. I tell you this because everyone tells me, well it is a new car with new plugs; they are never going to be the most premium. That is what is sucking your wallet dry.

2. Gas wise your doing great, you should only use 91, no matter what anyone has to say; the law of physics states that you get more power out of 91. Which saves gas! So your doing great on that part.

3. Oil by season, if you guys aint doing it, learn the meaning of TEMP breakdown; you should be! quality premium oil and VERY LOW OCI to maintain proper gas mileage is KEY!!! Manufactured recommended mileage is garbage

4. CAI, this is the final and most drastic step to saving gas. Multiple factors, proof lies in the 3g TL, you need to get a CAI; I do not know if it comes stock with the TSX so please dont be so quick to bash.
But not only CAI but you MUST WRAP your pipes with heat shield, because the metal of the intake is dramatically affecting the temp before entering the cylinder..

All of which is raping your gas, I get incredible gas mileage in my honda 4 banger and my Acura.

 

As usual DuckDodgers provided good advice.

"Premium" spark plugs will do nothing to improve your fuel economy, but they will last longer. Longer lasting plugs can improve your fuel economy if you neglect to replace cheaper plugs that are worn. Further reading here

Changing your air filter will do nothing to improve fuel economy unless it is causing an extreme air restriction to the engine. The largest source of air restriction is the throttle itself. When the gas pedal is pressed at any amount less than fully floored, the air intake is being purposely restricted by the throttle. What does that mean? It means you will only see an improvement in fuel economy using a high flow air filter when you are at full throttle. And if you are at full throttle, you aren't concerned about fuel economy anymore. Further reading here

A CAI (cold air intake) specifically will ever-so-slightly reduce your fuel economy. The loss won't be detectable, but it certainly will not improve fuel economy. In fact, those interested in getting the best fuel economy will do a WAI (warm air intake) mod which will improve economy at the expense of a small amount of wide open throttle power. Further reading here

Without knowing what your km/L or your mpg is, it's impossible to say you are getting good or bad fuel economy. Hand calculate your fuel economy at the next fill up so we know for sure what you are getting.

How cold is it getting where you are at? Warming your car before driving is very detrimental to fuel economy. Duck Dodgers had this absolutely right, but I want to emphasize it because of the importance. If you warm your car for comfort, you might try dressing warmer and just taking off moments after starting the engine.

A grill block can do wonders to speed up warm up time, which is key to getting good fuel economy. I installed one on my car and regained summertime fuel economy. I'll also brag here and say that I get the same fuel economy in stop and go traffic as steady freeway driving with my 6mt. Just realize that everytime you touch the brake pedal, you are converting the energy of burned gasoline into heat and brake dust.

I find that using instrumentation can greatly improve driving habits to improve fuel economy. The guage I use is called Ultragauge.

 

Here's another fuel saving tip; remember that when you are off the throttle, until the RPM's drop to or below 1,000, the flow is fuel to the engine is stopped.

The practical application of this looking ahead to the next light/lights. If the light is red, how long has it been red? If you know, and know it's cycle, adjust speed by taking your foot of the gas and allowing your speed to slow. Shift down, if necessary, to keep RPM's above 1,000. Another tip is to look at the pedestrian crossing signals. The newer ones with countdown timers are excellent for timing lights. If the light is green, how stale is it? Again, the pedestrian lights are useful warning signs of an impending red.

Anytime you slow with engine braking vs. the brake pedal, you are getting free extra gas mileage. My daily commute is 15 miles each way in heavy freeway and moderate city traffic with over 20 lights...even given that I average about 26 mpg while driving at or above the speed limit in the city by 5 mph or so and close to 70-75 on the freeway.

I know I can get 31+ mpg on the freeway portion by slowing to 55-60 and switching off the A/C.

I maximize use of engine braking and I try to swiftly get to a higher gear...by 40 I'm in 6th if the traffic allows it. That's the magic that gotten me 26+ mpg a tank since 2006.

 

thanks for the response guys. Can anyone recommend me a good website/place to purchase NGK Laser Irradium plugs? and i am looking to get an aftermarket intake. What is the pros and cons of an intake and what's a good brand? my car is completely stock as of now.