MaxMike93

Well I've had my I30 (thought I'd still post this in 5G since there isn't as much traffic in I30/I35 and figured there's be more insight here since my I30 is a 5G underneath the body) for almost a year and a half and really the only gripe I'd have with it is the mileage (EPA rated it at 20/28). Last year, it seems like I was averaging around 19MPG. Now, it's dipped a bit lower, with my only getting around 17MPG lately. My daily commute during the semester is approximately 13 miles each way, at about I'd say 70-80% highway and the rest is along slower highway/city driving. For anyone familiar, it's along the entire stretch of NJ-21 and then into University Heights in Newark, NJ. For a commute that is so much highway, I was just wondering if my MPG is lower than I should be getting since what I usually read is people getting mileage at least in the low 20s. I usually try to keep a 70MPH cruise on the highway, where the RPMs sit right at 2500. Otherwise, it may be slightly higher. I usually try to keep starts easy, but with all the nice torque these VQ engines make, sometimes its hard to resist . Should I try to clean my MAF? I didn't think that at about 44k it would be bad so I haven't checked. And my air filter was newer (and cleaner) last year so I may get a K&N drop in for that instead of just buying regular air filters that just get thrown away. I've linked screenshots of some stats I've gotten from filling up and logging into an app called Gas Cubby on my iPhone over the summer, with the better bits being from strictly highway drives to my family's shore house along the Garden State Parkway, and really no city driving at all in the summer either. If anyone has any input, please let me know and thanks in advance

Overall MPG since last June


Overall MPG about during my entire semester (this starts 10/13). I believe the jump there may have been from not having to commute while my school was out of service after Hurricane Sandy


General Stats

tosheto

iTrader: (5)

If you are getting 17MPG that's low. Is your SES light on? Anything broken? Have you done recent tune-up? Spark plugs, air filter, clean up MAF, etc?

Galactica

iTrader: (5)

It could also be an O2 sensor taking a dump. That is bad mileage for sure. That much highway you should be getting between 22-24 MPG.

MaxMike93

SES light is not on. I have not done a tune up since I was under the impression that it does not have to be performed until 100k. I'm thinking I'll clean the MAF and see if that makes a difference, get a new air filter, I could always try to get a look at the plugs. My friend is always working on his truck and sometimes I ask him for help with my car (I actually need him to help me try to pop a few dents out of my door that got put in a while ago).

Any idea which sensor? Like I said above, no SES light on, and I just replaced one sensor about a year ago, it was Sensor 2, Bank 2 (red wire) since I was getting a SES light for that.


Forgot to mention that in mid-October, I did have a P0420 code. I found a TSB on it and had the dealer reprogram the ECM since that was one possible remedy if my ECM met a certain serial number. Since the reprogram, the light has not come back on.

Prophecy99

iTrader: (1)

dont forget winter gas blends take 2-3 MPG away

Galactica

iTrader: (5)

A P0420 code is your firewall pre-cat inneficiency code, so I would replace Bank 1 Sensor 1 (the upper sensor) and more than likely your pre-cat is either clogged up or toast and I would either take it off and bang on it with a hammer to clear it up, or take a chisel to it and gut it completely. More than likely though that's your problem.

Rods03Max619

iTrader: (5)

Agreed doing so will gain you some MPG on the highway for sure, check the front 3 plugs and those should give you and idea of how the rears are, also should do the TC-W3 additive can also help you out, theres a Thread in the General Discussion section. Main things that majorly boosted my MPG, was Headers, Fuel Filter,anx TC-W3, get like 240 miles or more and have a heavy foot....when first got the car would get like 205-210 to a tank...

Quickywd01

iTrader: (16)

Clean the throttlebody and idle air control. Put in new spark plugs NGK only, change the fuel filter and air filter, synthetic oil and premium fuel, change the oxygen 02 sensors.

MaxMike93

Thanks for all the suggestions. I really hope the precat would be ok since I'm sure that would be a total PIA to get to/take off. I forgot to mention before also that I religiously run BP Ultimate 93 octane gas, with the exception of some stupid girl putting in regular when I told her premium once. I'll also look into the air filter since I'm wondering if that is dragging me down, as well as the MAF needing to be cleaned. I always thought something was up when I had a trip right to my shore house and back without much slower-paced driving and only averaging 25MPG when people here seem to get around 30.

Prophecy99

iTrader: (1)

i agree you are pretty low and need some tlc, but i will repeat dont forget winter gas blends are 2-3 lower mpg than summer.

fuel filter is big too if you can do it.

MaxMike93

I did the simplest things and just cleaned the MAF and put in a new air filter today. Maybe when it gets warmer out I'll look into getting a tune up to see if that would help. The pre-cat sounds like its a common problem, but I don't even wanna think about that nightmare that is taking it off to clean out

Galactica

iTrader: (5)

You just need a lift and the right tools and you'll be all right.