Bad gas mileage possibly other problems

[Engel]

Alright I dont know where to start.

Symptoms: I get 190 miles to the tank, maybe less
Gas fumes like I am running rich
Pinging at WOT on 89 octane
Inside of tailpipe blackish

Also, A very wierd surge at idle that happens maybe once in awhile (sometimes a couple days). This surge requires me to give it some gas or else the car will die. It is a fairly random occurrence and not too irritating but I thought it might be related.


I cleaned my maf a year ago at the MOST and it was not very dirty at all. My 02 sensors were replaced 2 yrs ago. My air filter is clean. Fuel filter was replaced not more then a year ago. Plugs cap wires rotor plugs was all done a year and a half ago. I am not leaking any gas.

How often do you guys clean your maf sensor and replace o2's?
Is it possible autozone o2 sensors failed already? I dont want to spend 100+ on o2 sensors if it is not the problem.

Any advice is always appreciated

 

[95GTV8]

clean the MAF, it's real simple, theirs a description on here somehwere on exactly how to do it, all you really need is a $20 tool you can find @ autozone or somewhere, search MAF in forums and it should pop up. I have no clue about your weird idle surges though.

 

[HISSIN50]

Have you pulled the codes? The CEL does not need to be on to trigger or store a code.

Cleaning the MAF and doing some tune up stuff (fuel filter, etc) is not a bad idea. I do fuel filters yearly - I dont have a lot of faith in fuel today.

Good luck.

 

[95COBRA241]

Have you pulled the codes? The CEL does not need to be on to trigger or store a code.

Cleaning the MAF and doing some tune up stuff (fuel filter, etc) is not a bad idea. I do fuel filters yearly - I dont have a lot of faith in fuel today.

Good luck.

Agree. also clean IAC. as for the pinging at WOT w/89 octane. what is timing set to. Either lower initial timing or use 93 or > fuel.

 

[yellowstang1994]

Our cars are notorious for pinging. I don't know too much about the surge personally because I never experienced it. But I hear a lot of of others had, you should check in to what they did to correct this. As for the last time you did the basic tune up items. I usually change my fuel filter every year. The wires cap and rotor seem fineas long as they look good, but I usually change my plugs every 6-8 months. (I get a drop of oil here and there on them sometimes because my rings have some wear on them). But really dude, 190miles per tank isn't tooo uncommon. It's not really bad but it's not great either. I'm not sure how you drive, but start there. I changed my driving habits a lot because all I could seem to get was about what you did. (Always thought there was something wrong with my car). I can about 250miles per tank in the city/highway. And a little bit more on all highway. Which is rougly 18-19mpg city/highway 22mpg all highway. If i'm trying to save gas I generally try to shift before or at 2k RPMs, and try to cruise at 1500rpms. I dunno though, good luck man.

 

[Engel]

I guess ill do the maf again, IAC and tuning stuff. Timing is set at the default stock level. I shift under 2100. As far as the fuel filter, I could have swore the haynes manual said you dont ever need to replace the fuel filter (long period of time), but perhaps I will change that anyway its cheap. Thanks for the help

 

[S/CBlack95GT]

You say you are getting 190 miles to a tank but what is your actual mpg?

 

[Engel]

i will calc it exactly next time I fill up

 

[Synned]

I am also getting **** mpg and it sucks. Fuel filter is up, I have done:
Plugs, distributer cap and rotor, wires, o2's, clean MAF, clean IAT.

 

[Mustangless]

last time I filled up I only got 11mpg. And that was driving like a old person. I do not have any pinging though but my performance is very bad.

no codes, no cats, new air and fuel filter, ran seafoam, cleaned iac, throttle body, and maf. New plugs, wires, cap and rotor. Timing on 12deg I am out of ideas

 

[pwr4all3]

last time I filled up I only got 11mpg. And that was driving like a old person. I do not have any pinging though but my performance is very bad.

no codes, no cats, new air and fuel filter, ran seafoam, cleaned iac, throttle body, and maf. New plugs, wires, cap and rotor. Timing on 12deg I am out of ideas

I am in the same boat, except I managed to get 13.8 mpg! I cleaned the maf a year ago and have since switched to a K&N. It seems like since the K&N was on milage went down after a few months. I took apart the maf today and cleaned it with electrical cleaner and compressed air in the car. I really hope this takes care of it. I think you and I might have to look to a compression test next. at 3.00 a gallon you can no longer ignore milage this low.

- Randy

 

[Grn92LX]

Engel, have you done the math to see what you're actually getting for mpg?

 

[pwr4all3]

Well after cleaning the MAF it made no diffrence at all in MPG. I am still getting bad Mileage.. Tonite I avaraged 11.2 MPG.


- Randy

 

[Mustangless]

Well after cleaning the MAF it made no diffrence at all in MPG. I am still getting bad Mileage.. Tonite I avaraged 11.2 MPG.


- Randy

That sounds about like my car. I don't get any pinging though, never have. Its just really weak

 

[Synned]

That sounds about like my car. I don't get any pinging though, never have. Its just really weak

Is your problem all the time mustangless? I used to think we had the same problem, but the very first time I start the car it has a lot of power. It's so weird, but I still get the worst MPG! It really seemed like the o2's worked tremendously, like for 3 weeks any time I wanted to I could chirp the tires and now its starting to freakin hesitate again.

 

[Mustangless]

Is your problem all the time mustangless? I used to think we had the same problem, but the very first time I start the car it has a lot of power. It's so weird, but I still get the worst MPG! It really seemed like the o2's worked tremendously, like for 3 weeks any time I wanted to I could chirp the tires and now its starting to freakin hesitate again.

I think my problem is the entire time, cold or hot. I am getting so mad because I get no codes, and have replaced just about everything.

 

[Synned]

I know, its such a bitch. Just think though, in the future this problem WILL be fixed. You just can give up! . Theres my pep talk.

 

[95COBRA241]

All this complaining about gas mileage. What did you expect with an 8 cylinder car? Those ratings of 18 city and 24 hwy are best case scenarios for people running 10 degrees timing, cruising at 60mph, with 2.73 gears in fifth gear. Stop and go driving in the summer with a/c on in a modded mustang...equal 10-14 mph all the time.

 

[Synned]

All this complaining about gas mileage. What did you expect with an 8 cylinder car? Those ratings of 18 city and 24 hwy are best case scenarios for people running 10 degrees timing, cruising at 60mph, with 2.73 gears in fifth gear. Stop and go driving in the summer with a/c on in a modded mustang...equal 10-14 mph all the time.

Um, there is something wrong when slow driving with our cars nets 10-14mpg. There are plenty of people on here with HCI stangs getting around 20mpg, and we are just trying to fix our problem.
BTW Great advice! We'll just ignore it! YES!

 

[pwr4all3]

All this complaining about gas mileage. What did you expect with an 8 cylinder car? Those ratings of 18 city and 24 hwy are best case scenarios for people running 10 degrees timing, cruising at 60mph, with 2.73 gears in fifth gear. Stop and go driving in the summer with a/c on in a modded mustang...equal 10-14 mph all the time.

There's a MPG diffrence between driving "spiritied" and driving like "granny" We are simply saying that even under those "ideal" variables we are still getting 10-14 mpg. Anyone with any comon sense can clearly see something is wrong when MPG is so low. Nothing usefull to contribute to a functional thread? then just don't post to it. It's that simple.

- Randy