Horrible gas mileage!!!

[immajackuup]

BUMP. Tired of getting less than 23 miles to the gallon. Does anyone know the symptoms of a bad afm? My AFM has been expose for awhile now and I think this might be the reason why the gas mileage isn't that great... The car also having horrible idle at the start. I would hesitate to any kind of throttle response. I'm very confused because this same car passed smog not to long ago..

bad injectors,might as well get your self mustang injectors. I myself was in the same boat as you op.

also the 92 and up m42/44 motor injectors convert to 4 pintle.

http://www.fuelinjector.citymaker.com/catalog/item/4494564/4532416.htm

plug and play,I used to get 16miles to the gallon or less but as I change the injectors now is 24miles per gallon. also the 4pintle mustang injectors will make your motor alittle less noisey.

http://m42club.com/forums/showthread.php?p=104404#post104404

[keada714]

BUMP. Tired of getting less than 23 miles to the gallon. Does anyone know the symptoms of a bad afm? My AFM has been expose for awhile now and I think this might be the reason why the gas mileage isn't that great... The car also having horrible idle at the start. I would hesitate to any kind of throttle response. I'm very confused because this same car passed smog not to long ago..

[keada714]

I replaced the O2 sensor last week and it seems like its getting better gas mileage but still pretty low for a 4 cylinder car. Haven't tried to change anything else because I been so booked with work..

[Ryann]

Seems to me like you would fail smog testing with that kind of mpg if it were management related.

[SiGmA_X]

Update? Similar situation here, but 17mpg.

[keada714]

I'm on it! Thanks Ken! You've been very helpful throughout all my threads!

[KenC]

Coolant temp sensor, and O2 sensor would be my advice.

[keada714]

My idle is pretty stable and idles around 850 give or take. I believe I put the two lines together correctly since I've been driving the car for more than 2 weeks now without very little problems that I have fixed, aside the fuel consumption.

I believe California has the one of the most strict emission DEQ test. It pass without a problem. So I'm not to sure what I should replace.. Ideally I would like to replace the parts that I only need to since I'm a struggling post grad trying to get on my feet (maybe I shouldn't have bought a Bimmer!).. Going to replace a couple sensors and I'll keep you guys posted. Thanks again for the advice!!

[KenC]

How much is a DEQ sniff test where you live? High carbon levels usually always point to a rich mixture. Might be a good place to start and get some objective data.

[KenC]

I've done the vaccum hose delete under the intake and replace them with new lines. Some heater house (larger one) and vac lines. I just remembered when I removed the lower intake it required me to remove some fuel lines. I believe there is two fuel line coming up form the chassis to the fuel rail.. Would it matter if I swapped those two line around? I forgot which line goes where so I just made a educated guess and left it. I was wondering if anyone have a picture of can direct me in the right direction and would this effect my gas mileage..

It wouldn't run if you swapped them.

How is your idle? The M42 is very susceptible to vacuum leaks. It should be very smooth. If it isnt smooth, you may have a leak.

Get a mid 90s mustang gt O2 sensor and just buttclamp the wires to match colors.

[keada714]

Thanks for the suggestion!

[bmwm42]

Order all and any parts you need from blunt. You will get them next day.

[keada714]

Order what from blunt.. One two?

[keada714]

I've done the vaccum hose delete under the intake and replace them with new lines. Some heater house (larger one) and vac lines. I just remembered when I removed the lower intake it required me to remove some fuel lines. I believe there is two fuel line coming up form the chassis to the fuel rail.. Would it matter if I swapped those two line around? I forgot which line goes where so I just made a educated guess and left it. I was wondering if anyone have a picture of can direct me in the right direction and would this effect my gas mileage..

[bmwm42]

Order from blunt for one two yes those vac lines are a gas killer if they are leaking.