Horrible Gas Mileage

01OhioAlero · 07-13-2014, 03:35 PM

Since I got my car running I filled it up and put the trip on. I have gone 82 miles from full and Im almost at half a tank. I expected to get at least 150 per half tank. I rarely floor it only like once or twice and I drive normally and baby my car. Pretty much every tune up thing is new (plugs, wires, air filter) so Im stumped. I think its my cat possibly, because my car is hard to start sometimes.

rocketfast321 · 07-13-2014, 07:14 PM

What motor?

01OhioAlero · 07-13-2014, 07:23 PM

3.4 i think it might be fuel filter since i dont think it was ever changes

sleepyalero · 07-13-2014, 08:01 PM

O2 sensor will also cause bad mpg.

a.graham52 · 07-13-2014, 08:43 PM

http://www.aleromod.com/forums/showthread.php?t=37712

number53alero · 07-15-2014, 10:56 AM

Yeah I need to as well, I can squeeze 300 miles per tank if I keep it under 2k RPMs the whole way with a 50/50 mix of city/hwy...

01OhioAlero · 07-15-2014, 12:15 PM

Its not 02 because I would have a check engine light right? Pretty much everything you did I have done besides fuel filter...But I looked and my lines are reallly crusty I dont think I can get it off without at least kinking them and that will make a crack. And Im gonna also do the flashlight test for air leaks.

rocketfast321 · 07-15-2014, 07:37 PM

Now really, they can get lazy over time. This was mine at 109k in my old grand am.

I kelp a heavy foot so my mpg was crap. But still not better in my alero my alero. Maybe its in my head but i try to run 89 gas at times or ethanol free gas to help mpg.

I also use Lucas fuel treatment. But this post from bob the oil guy fits me.

Quote:

Any time I ever used it it seemed to help mileage however it never lasted. 1 or 2 tanks were better then mileage would slowly return to normal.
It almost makes the consider that the engines ecu calibrates mileage. Once it gets too good the ecu does something to make the fuel consumption come back to programmed parameters.
I've found if I alternate different products and keep the ecu guessing I can routinely beat the advertised averages.
Tin foil hat on

tacollins · 07-15-2014, 07:39 PM

(dealing with under body dirt/grime)
I'm guessing they are crusted with dirt or road grime, What I usually do since I don't have a pressure washer is take it to an automatic car wash with a real good under body sprayer. If you do this make sure it's a touch-less wash, I learned my lesson on the ones that beat the car with those brushes or whatever you call 'em when mine came out with a scratch from a piece of gravel or something caught in the brush thing. If you have a pressure washer you could probably use that.

(possibly useful info on my car)
Talking with my dad and the best we can remember the one I have (2004 coupe) has metal fuel line from the filter to the engine and either a metal or braided fuel line from the tank to the filter. I dunno if the older ones had rubber line like is on my cutlass but the lines on my car can't be kinked... you'd need a new fuel line.

(pretty useless info on my car)
Mine used to get 26 mpg, but my lifters are going bad and the local gas is eating my car >.< (the gas is so bad it actually feels like the tranny is going out, heet is awesome in this case) I'm figuring I'm now getting 20 mpg now about 190 for every 9.5 gallons (approx. 3/4 tank)

01OhioAlero · 07-15-2014, 11:31 PM

Yeah, Im not touching that fuel filter. I will need new fuel lines guaranteed. So...time to take it to dealer and have them do it. It breaks its their fault. In the meantime I found out my car had factory fog lights but got taken out when it had a front end wreck.

01OhioAlero · 07-16-2014, 12:21 AM

And my ac compressor is bad...Has anyone done a ac delete on their car? Its making this annoying sound thats like a hissing kinda. If I pour some water on it it quits till its dried up.