Gas mileage ugh...

[click]

Well, where to start. My 94 mustang with cai, o/r x pipe and cat back gets maybe 11-13 miles to the gallon. And honestly that is with really no getting on it WOT. I usually shift at 3,000 rpms.
During summer time i was getting pinging, running 91 and at 10* timing. I cleaned my maf, and ran seafoam. And the pinging seem to stop.. As soon as i boosted the timing to 12* the pining came back.

So to jump ahead my timing is at 10* again. If its real hot and i go WOT i get pinging, but my gas mileage is what sucks.
I have used seafoam, lucas fuel injector cleaner. I did plugs, wires, cap, rotor, fuel filter not that long ago. Cleaned my maf 3 times, act twice, ect, and throttle body. All the sensors i could find and unplug i cleaned with electrical cleaner. I have tried 91, 89, and 87 gas just to see if that changes everything and all i got was pinging at wot using 87.

So what else could it be? Possible compression loss due to blown/cracked head gasket. Keep in mind the car has 110k miles on it and probably never has the gasket changed. Or maybe clogged fuel injectors even after that lucas stuff. My O2 sensors seemed okay when i did my new o/f x pipe. I don't hear/see any vaccum leaks... I'm really stumped...

thanks for any responses...

 

[Engel]

I only get 200 miles to a tank... however shifting under 2k should help you some.

 

[WhiteDevil]

I usually get 225 or so to a tank. You should try new O2 sensors. Since they control your closed loop operation which is where you save the most gas i would look there.

 

[JJ95GTID]

Tire pressure good? How's your front end alignment? Air filter new/clean? Maybe cleaning your sensors isn't working. Start replacing them. If your car is still pinging something ain't working correctly which can translate into poor fuel economy.

 

[OinkAodeOink]

bad 02's or even old 02's will kill fuel economy. After I replaced mine ( in the 94) the car felt completely different as far as performance, not pinging, and gas milage.

 

[95COBRA241]

O2 sensors, fuel filter, air filter...clean and/or replace those items. maybe new colder plugs.

 

[BlueOvalStangGT]

I got 14 MPG HIGHWAY on the way here to Tampa last week. Thats 100% highway too, but I did have my A/C on.

 

[Engel]

how long do o2 sensors generally last?

 

[Mustangless]

I am starting to think I need to replace my o2s. My car runs like crap and I get about 11 mpg

 

[legalize420]

i get about 19-20 mpg driving in bumper to bumper rush hour traffic every day with 87 and 10*. i usually fill up at about 260-270 and can fit about 13-14 gallons in the tank. are you having any other noticeable problems that might contribute. my car has 120,000 miles and i havent changed my o2's yet.

 

[mo_dingo]

As O2 sensors degrade with time, the car will run leaner and leaner. So that may explain why you are pinging at part throttle.

So replace the O2's if you haven't done so already.

But as to your pinging at WOT, you might want to replace your IAT sensor...And maybe your MAF sensor too. I don't know if it will cure your problem, but the elements may have degraded with time and no cleaning will cure it.

Another thing you should check is your fuel pressure w/o vacuum, and get a vacuum gauge and see if it's steady and around 22 inches.

If you suspect a HG problem, a leakdown test may be your only solution.

A side note. Cleaning my MAF was the major cure to my pinging. But when it's 110 out, my car still pinged, no matter what I did. The only solution was to grind all of the carbon off of the pistons and replace my heads. No amount of sefoam will get rid of a 1mm thick carbon layer on the pistons and combustion chambers. But that definately got rid of it and you may have to do the same.
Scott

 

[interex1982]

i get 18-22 and my car pinging anytime its hot outside which my timing is 14

 

[ponyboy19]

My 92 which is pretty close to stock with and AOD and 3.27's will get 22-24 driving in all kinds of conditions and limiting how far the throttle gets pushed down. That is with original ruined O2's that trigger a check engine light. (one fell out and bounced off the ground for about 10 miles.. So it is possible to get decent fuel milage out of them. I think it's all about how you drive it and how far the pedal gets pushed.. I can cut that down dramatically if I drive it like I stole it all the time. Which I actually preffer to do, just not a $3.00 a gallon

 

[Stang95fyvo]

I got 14 MPG HIGHWAY on the way here to Tampa last week. Thats 100% highway too, but I did have my A/C on.

I went to Yakima WA one day and had the cruise on with A/C and got 25.5 mpg. Then on my way back to Portland I was doing 85-90 following a Vette, 2003 Cobra, and a CTS-V and still got 24.5 mpg with the A/C on. Something is definitely wrong with that guy's car.

 

[click]

i know my gas mileage sucks damnit

 

[95snoozer]

i went 360 miles on 14.x gallons the other day.

Had my 290 pound roomate in the car and a spare iron 5.0 for half the miles
fuel pressure is like 46 vacuum on