waz up guys i need some suggestions...

MPG is crappy !!!
what sould i check on?


all filters are new
plugs are new
what else???
thanx

 

O2 sensor? You can also use a diagnostic checker thingie to see if something's wrong.

http://www.teamfc3s.org/info/article...ctor%20Chapter

 

i have the same issue... haha! less than 10mpg depending on how much street i drive...

but i pretty much think that its running fine?.. no engine codes or anything.

i smell a little gas from the exhaust but how would i go about adjusting that? if it is running rich.

i do have a HKS plug anf play F-Con, maybe thats why its running rich?

and are the rpm cut offs at different RPMs for each gear?

i find that i cant rev past 5-6K in first gear, about the same for 2nd, 7K for 3rd, about 7-8K for 4th havent been able to go all the way in 5th...

but 4th gear tops off around 115mph, is that about right?

 

First, exactly how are you measuring this? A car that only gets 10mpg is normal driving won't be running very well, so are you sure it really is that bad? It there a strong exhaust smell? Do you see black or brown smoke under load?

Oh jeez, not again...

A faulty or disconnected O2 sensor CANNOT cause such bad mileage! How many times does this need to be explained?

 

Had sort of the same problem. This may sound crazy but check your coils, had one going bad and mine did the same thing.

 

To the original poster, how old is the car? Low compression can be a cause of bad gas milage. Does it have cats? If so, they could be clogged. How does the car run? Does it feel like it can barely rev, or does it run fine?
And to the guy with all the caps in his name, there is something wrong with your car. The rev limit is the same in all gears - over 8k. Do you have an FCD? You might be hitting fuel cut.

 

Bottom line is how is the car running. Two equations possible way I look at.

1. Car runs like ****
2. He can’t add.

3. O2 sensor knowledge must be added to the FAQ.

 

Rebuild Injectotrs

 

my "street" ported rotary got 15mpg....ON THE INTERSTATE!

 

Ours was bad, idk what was wrong with it but it gave different readings almost woeking backwards it seemed

I replaced it with a good one and now the gas smell isnt as much in the cabin anymrore

 

I had a similar problem when I got mine... Only I got 6.5 mpg... I do 90% of my driving on streets and the other 10% on highway... I changed my plugs, wires, and set the timing... I changed the fluids(all of them) and fuel and air filter... When I was done I got about 10 mpg... I changed the O2 sensor and got 12 mpg... I then ran an injector cleaner through a full tank of gas and got about 14 mpg... I calculated this by resetting my tripometer when I fill up... When I fill up again I will take the amount of fuel put into the car (down to the thousandths of a gallon) and devide it by the miles accumulated on the tripometer... So the O2 sensor, although small, made a difference... It was definately not big though... My car has run very well (meaning no noticable defects) when I got it and still does...
Now, as far as smelling exhaust... My car smells like exhaust when I am on the highway and the sunroof is open... I can roll down the windows and be fine though... Other than an exhaust leak what woul that mean? I do not get smoke except when I start the car on ver cold mornings and it is usually white... And it smells so gassy that I considered holding a lighter to it for ***** an giggles... I just dont think my home owners insurance will see it my way...
I am going to go breathe now... Sorry for the long winded reply...

PS - 89 NA Stock

 

This is why I don't drive the FC every day....

 

New fuel filter
Check Pulsation Dampener
Check fuel pump
Have injectors cleaned/rebuilt
Check for a fuel line leak

these are most of the reasons you would have that bad of gasmileage, but for the fuel filter, its cheap, replace it anyways

 

My car runs fine, i occasionally kill some cars on the street to keep it in shape

transmission is beautiful and i get stuck to the seat cause its nice and fast.

i never checked the O2 sensor and i need wheel alignment cause the car pulls one way and after i hit a bump it pulls another way !

i got a hunting idle and that must burn some gas.

I DO SMELL GAS !!! and i think its from the exhaust.

Right now my car sounds like crap!!!
like an old beat up TERCEL if you know what i mean...

 

Here's how to check your MPG the right way...

1. Fill up the car until the pump stops automatically
2. Write down the mileage
3. Drive
4. Fill up the car until the pump stops automatically
5. Write down the mileage
6. (New Mileage - Old Mileage) / (Miles Driven) = MPG
7. Post again with what you get

It's best to do it a few times. I get varying results (I do this EVERY tmie I fill up). I get anywhere from ~14 to ~23 mpg depending on how, where, and conditions of my driving.