I have a '98 SOHC with 85K. New plugs, wires, coil, air filter, fuel filter, and most other maintenence is current and the best I can do is 14 city and 17max highway. My foot isn't that heavy I don't think! Does anyone know of a legitimate way to increase fuel efficiency?

 

No.

You have what you have. A big brick with a high-revving v6 on wheels on a 4x4 frame--even the 2wd versions are on the same 4x4 frame.

You are par for the course with Exploder fuel mileage.

 

You can try running a higher grade(93) gas, but that only pays off if you are doing a lot of highway miles.....

 

Have it diaged..maybe one of your oxygen sensors is bad. That would definately affect mileage providinge you had better mileage before. Another way to free up a couple of miles is free flow intake and exhaust.

 

hey i have a ? for u would a bad sensor not turn on the CEL and couse me to have bad milage i have a 91 exploder with 137K maintance is up to par but i am only geting 9-10 mpg city and i have been light as hell on the gas

 

I was wondering about the TPS unit. My 93 bronc's was bad and it didnt send a CEL but once I replaced it helped a little.. Does that make sense? I thought a bad O2 sensor would send a CEL?

 

I had the same problem running around 14 mpg to around 230 per. tank. But I got a sct chip and my mpg went up to 310 to 320 per tank on 87 oct. CITY DRIVING Talk to Ken at Motorhaven.

 

Thanks for that I will look into it..

 

If the oxygen sensor, or mass air flow sensor is completely dead, you will see a CEL.

However, both of these sensors degrade slowly with age. The oxygen sensor responds slower and slower to changes in mixture ratio, resulting in a feedback loop with more phase lag, and less accurate control of rich vs. lean. The mass airflow sensor gradually accumulates contamination. This causes it to read too low at low airflows, and too high at high airflows. The result is a rich mixture at low speeds, and a lean mixture at high speeds. The computer can compensate for this to some extent with feedback from the oxygen sensor, but as I said, it too is getting old and slow. Expected oxygen sensor lifetime is 60000 to 100000 miles. If you exceed this, the engine still runs, and the CEL light does not come on, but the performance is not quite what it should be.

My 1996 Explorer with the 4.0 engine had 109000 miles. I was able to noticeably improve engine smoothness and boost gas mileage (up about 10%) with the following regimen:

1) Replaced all three oxygen sensors
2) Removed air cleaner housing and sprayed MAF sensor wires with electrical contact cleaner
3) Disconnected battery ground cable for 15 minutes

Step 3) is necessary to force the computer to relearn engine behavior in the face of the new sensors. Otherwise, it will take several weeks for computer to "unlearn" the old and now incorrect values.

 

Yeah I have replaced one of the O2 sensors on my dad's exploder it was a b****! It was rusted tight and once we got it off the threads on the Y-pipe were completely shelled.. That was a fun weekend! The MAF sensor is between the air filter and the throttle body??

 

Autozone will rent you the three tool set to change oxygen sensors. It doesn't even cost anything other than a deposit on the tools. On a 1996 and later Explorer you will need two of the tools in the set. Use the deep socket on the sensors where it will fit, and the crow's foot adapter on the one sensor that is up too close to the floor pan. On a vehicle this new, in a place that doesn't use a lot of salt on the road, the sensors should not be rusted tight.

The oxygen sensor is in the plastic housing just after the air filter. Do NOT try to touch it with a Q-tip or any other mechanical object. Do NOT spray it with carb cleaner.

 

There are several things you can try... You can get a K&N FIPK which will lean your A/F mixture a bit. Also, you can try a more aggressive tune on your ECM to lean the engine a bit (you'd want to dyno verify you aren't too lean though). And, you can try a free flowing exhaust which should help some too.

 

Is there a way to adjust ECM configurations without getting an aftermarket tuner?

 

I think there are some computer programs floating around that can be used with a laptop if you have the right cables. I'd rather buy a tuner from someone like Predator or Hypertech though.