12mpg...Sound about right w/ 4.10s + roof rack?

[audiquattrot]

I've been monitoring my mpg more closely these days, and have noticed I'm only getting 12-13mpg!!

Car has been running better than ever, but obv something is wrong here. A couple factors also come into play including the fact that I have a roof rack + 4.10 diffs on a manual....but would that be enough to bring my mpg that low?

I use my rack a ton both in the summer (mt biking) & winter (snowboarding)....so taking it off isn't really something i'd want to do....but I might remove it to see if it helps (which i vaguely remember it not making much of a difference).

Just wanted everyone's input if I should start by replacing the O2 sensor and/or having my AFM rebuilt....to try and get the car running more efficiently.

Some of the things that I recently replaced:
-spark plugs
-spark plug wires
-air filter
-intake hose

Thoughts?

[dannyyisntt]

I get better than that in my ix and it runs like shit most the time..

[audiquattrot]

I get better than that in my ix and it runs like shit most the time..

lol...yeah its pretty bad, but i have to tell you this car runs smooth as hell...smoother than my E46.

yeah i'm curious to see if anyone here is still running the 4.10 diffs after their 5-speed swap...and what mpg their getting. I didn't think it would have a significant effect on the mpgs...assuming this is the cause of the poor mileage.

[e34_spangler]

you could try a used 02 sensor some where but when mine went out in my E it was causing problems so i doubt that... maybe the ecu is screwing with something? idk thats a long shot and theres diy's on afm's you could try that

[chuckdizzle]

keeping the rack on all year won't really affect fuel consumption. Changing the o2 sensor is a good start and I think should get you back to normal fuel efficiency.

[PorscheDude]

I'd say that's about right for the amount of stop and go traffic in SI.

[audiquattrot]

you could try a used 02 sensor some where but when mine went out in my E it was causing problems so i doubt that... maybe the ecu is screwing with something? idk thats a long shot and theres diy's on afm's you could try that

yeah i saw a diy on afm's, but prob not something i wanna tackle since its beyond my knowledge on how those things even work. lol I can swap it out no prob, but tinkering w/ the internals is def something i'm not comfortable with.

keeping the rack on all year won't really affect fuel consumption. Changing the o2 sensor is a good start and I think should get you back to normal fuel efficiency.

yeah I'm gonna order a new O2 sensor. Hopefully it makes a diff. I'm not big on additives, but I'm going to try fuel injector cleaner to see if that helps as well.

I'd say that's about right for the amount of stop and go traffic in SI.

lol Actually 95% of my driving is highway since I commute to NJ for work (reverse commute)....so I'm never really sitting in stop/go traffic....but i do agree this area is plagued w/ traffic.

[audiquattrot]

ironically enough, the CEL light flashed on for a couple seconds on the drive home today. I've been getting poor mileage for quite some time, so for it to come on today after posting this thread is a bit coincidental. Unfort the Peake tool i use on my E46 M3 doesn't work on the E30, so i'm curious to see what codes pop up.

[downforce22]

I've got 4.10s in a 5 speed and I get 22 average here in colorado. I'd get an 02 sensor and maybe clean the fuel injectors or change spark plugs.

Click the link for stats on my cars mileage over the past 3 years

http://www.fuelly.com/driver/downforce22/325ix

[audiquattrot]

I've got 4.10s in a 5 speed and I get 22 average here in colorado. I'd get an 02 sensor and maybe clean the fuel injectors or change spark plugs.

Click the link for stats on my cars mileage over the past 3 years

http://www.fuelly.com/driver/downforce22/325ix

That's good to know...thanks for your response!

I'm gonna order a new O2 sensor tonight. Ill update this thread to see if it made a difference

[nando]

12Mpg isnt normal in any condition. I get 19-21 hwy with a thirsty stroker and 4.10s. Even city driving is never less than 16-17.

[audiquattrot]

12Mpg isnt normal in any condition. I get 19-21 hwy with a thirsty stroker and 4.10s. Even city driving is never less than 16-17.

i'm jealous. Hopefully i can solve this sooner than later. Driving the E30 400+ miles a week to/from work, filling up twice weekly is def taking quite a hit on the wallet.

[downforce22]

I just changed my oil and I noticed my mileage is better this tank.

[Dirty325ix]

I've got 4.10s in a 5 speed and I get 22 average here in colorado. I'd get an 02 sensor and maybe clean the fuel injectors or change spark plugs.

Click the link for stats on my cars mileage over the past 3 years

http://www.fuelly.com/driver/downforce22/325ix

glad to hear I was worried that I was going to loose all of my money on gas on my 5 speed swap

[mclawrence]

also check for fuel tank leaks