Bad gas mileage?

[stsmoker]

The MAP sensor, air flow sensor, temp reading, and many other things can determine the fuel:air ratio. Like shadow said though, leave overdrive on unless towing or driving on extreme mountainous terrain. Maybe check for a vacuum leak? but usually that triggers the Check Engine Light.

You dont have a hole in your gas tank do you? lol

 

[tripplec]

The MAP sensor, air flow sensor, temp reading, and many other things can determine the fuel:air ratio. Like shadow said though, leave overdrive on unless towing or driving on extreme mountainous terrain. Maybe check for a vacuum leak? but usually that triggers the Check Engine Light.

You dont have a hole in your gas tank do you? lol

How long or what determines how quickly the computer optimizes itself?

Now that I think of it. Yeah there is a small hole. But I never gave it much though. I think of it whenever I have to add gas to the tank. It's hidden behind a door which has as sealed cap. Hmm never though it would leak of of there, input only hole.

 

[bichon]

My bet is on the plugs and wires. My mileage improved 20% when I changed them. There was 60,000 miles on the original plugs in my 97. The old plugs looked like normal wear except two had significant fuel additive buildup around the electrodes. New plugs Improved my power and hot restart quite a bit too.

 

[Silence*]

Ummmmmm....you actually have zero idea if you are getting different gas mileage. As mentioned above, you have to divide the miles/km driven by the KNOWN gallons/liters used. You also need to average it over more than one tankfull to take into account variances in how "full" the tank is when you stop pumping. There is no way to know unless you do it that way. The gas gauges may be calibrated differently (gas gauges are an estimate of how much fuel is in the tank, they are not accurate), fuel tanks may have been filled differently (one person's "full" may be different than another's, and the gas station nozzles may shut off at different pressures), fuel tanks are different size, etc.

I know that... I was just assuming it was bad and I was right. As I stated a few posts ago, I get 265km's on 55L (= 165 miles on 14.5 gallons I think?) of gas everytime (unless I do highway driving). I'm doing plugs and wires thursday, along with a fresh oil/filter and air filter change, topping off my tire pressure, and if I have time I'll try cleaning my MAF and doing a o2 Sensor. hopefully this helps, I hate burning through $40 of gas every 3 days, lol!

 

[stsmoker]

Sometimes it takes the computer forever to find a problem, sometimes it never realizes theres a problem. And many many people have leakin gas caps, more than you would think, But i think if your loosing that much gas than you would definately notice some kind of puddle or smell gas or something. Might have a fowling plug, although that 'usually' throws a misfire code. I would definately start by changing the plugs and wires, but just dont think that would be the only problem unlessss you do have a bad plug.

 

[tripplec]

I just took it for a run around. It pull fine and hits 80kmph within a short block between speed bumps, took that speed bump fine at 80 by the way. Reving in part I noticed it surges and can pass 3000RPM. My mechanic says they have a rev limiter on them so its normal. I am going to have the fuel filter changed tomorrow anyway.

 

[tripplec]

Well I decide to have the fuel filter replaced. I had the three pipe type in my vehicle. The way the gas gushed out of the lines when disconnected and how it drove makes me dubious that it has any relation to an millage issues. However, now I know its new and it appears the previous was original anyway. All the hoses, plug wires look like new under the hood, clean and nice and blank rubber surfaces except for the plug wires which are grey OEM.

 

[tripplec]

Sometimes it takes the computer forever to find a problem, sometimes it never realizes theres a problem. And many many people have leakin gas caps, more than you would think, But i think if your loosing that much gas than you would definately notice some kind of puddle or smell gas or something. Might have a fowling plug, although that 'usually' throws a misfire code. I would definately start by changing the plugs and wires, but just dont think that would be the only problem unlessss you do have a bad plug.

Not loosing gas, but using gas and being just purchased it would have been E-tested by the dealer.

 

[bfcerny]

So did wires and a filter fix it?

I am getting about 186 miles on 14.5 gallons. I changed my fuel filter and cleaned my injectors and have not driven enough since then to see if it helped. Did you changed the plugs and wires? Did it help?

 

[tripplec]

Fuel filter

I am getting about 186 miles on 14.5 gallons. I changed my fuel filter and cleaned my injectors and have not driven enough since then to see if it helped. Did you changed the plugs and wires? Did it help?

Fuel filter only, The plug wires look are clean and look like new and I cannot see the relationship in mileage and a bogged up filter. But not being the original owner I decided to change it at that point. The O2 sensors and injectors are the likely components responsible since my truck which I got for my son but do the repairs for him. I need to get it on the highway again and see if its recalibrated or learned the settings. Maybe with it being very cold its throughing off some of the feedback values or just running much richer due to the cold weather. Might try injector cleaning additive soon. I have Jeep Grand Cherokee and changed the plugs last year. Mileage did not improve despite the state they were in. I put in some High Octane gas from Petro Canada which has a high dose of Tractor Cleaner a moment ago.