I have been trying to figure out why my 2000 dodge durango 4x4 with a 5.9L had a loss of power and really bad gas mileage since 40,000 miles. Below are the things I did but never fixed the problem.

Intake, Exhaust, new plugs, new rotor and cap, new msd ignition wire, throttle position sensor, O2 sensor, etc.

After years of trying to figure out and trying everything in the book on how to improve fuel economy. I just about gave up.

Well, I had an issue with another dodge car where the map sensor went out completely. So, I gave it a shot on the durango as well. So, what does the map sensor do? It tells the computer how much pressure is in the manifold. Thus, telling how much fuel to pump in. Take a look at your throttle body, it will build carbon over time. The map sensor has a diaphram inside of the sensor, so over time carbon build up and the diaphram hardening up will not cause the sensor to fail but rather read inaccuratly.

After I replaced the map sensor:
Power return to like a new car condition
My gas mileage returned
Runs like a new car again
Engine no longer knocks

Those of you with poor gas mileage issues that have replaced everything else, may want to give this a try to get their gas mileage back.

I remember When I first started trying to figure this out, people with the 5.2L also had this problem.

 

Woot! I thought the MAP would be suspect but was reading good off the car... I guess I will give mine a try... Should be cheap enough! Thanks for the update!

 

Neo,

Spread the word once you have tried this and worked. It will help a lot of dodge owners with 5.2L & 5.9L magnum engines with very poor gas mileage.

Note: The cheapest map sensors were at Pep Boys or autozone.

 

LOL! Wow! $80 for a MAP? Ya know, it is funny how parts pricing works... The cheap stuff for America cars is the money maker on European cars and the expensive stuff on American made cars are the cheap parts for Euros... Go figure!? A MAP for my Turbo Audi was only $20... O2 sensor was $300 and one for the Durango is only $40... Who'd-a-thunk-it?

 

To give you an idea about gas mileage, I was getting 13-15 mpg on the highway with the old map sensor at around 70mph. Now with the new one at cruising I get 18-22 mpg on the instant mpg monitor.

Huge jump in mpg. With gas prices the way they are, your map sensor will pay for itself in no time.

 

Hmmmmmmmm!

I'll keep it in mind. What about you Kensai?

 

What is Kensai?

 

Kensai = board member getting like .003952 MPG...

 

ha ha ha ha, Now that's funny, I feel sorry for the guy.

He would be a great canidate to try this.

 

Yeah, I am always the sorry feeling kinda guy! haha. Just driving around town and putting an egg under my pedal, I still only avg around 9-10 mpg. When I took it out on highway on a fresh full tank and drove like 50 miles, I only see around 12-13 at best. Definitely something not right. I use to hang around 11-12 in town and get 13-15 highway.

I will let you guys know as soon as I get my map sensor from Napa today and have it installed. Just gotta find where the sensor is located at.

I will give that a try before the O2 sensors then. It would make sense given the age of our D's. Now someone tell me where the map sensor is located? I am heading off to my local NAPA store to buy all the tune up stuff in preparation to drive my Durango from DFW to Denver and back this coming 4th July holidays.

Tuneup list:

ATF+4 - replace tranny fluid, did not change fluid in the 5k miles I driven on the new fastman tranny. So time to change it just to get all the servicable fluid that was in the tranny when it was rebuilt.

Castrol syntec 10w30 oil change

valve cover gasket/seals - damn driver side started to leak. I just hate seeing any oily residue anywhere on my spanking clean 5.9 engine!

O2 sensor replacement - Now that someone shed some light that it may be a map sensor issue, I will replace the map sensor first. I assume this sensor is much much easier to get to and replace vs. the O2 sensors.

Now replacing the map sensor, I assume you reset the PCM after replacement so it will learn the new sensor?

I wonder if the map sensor is the problem giving all the 5.9 owners here various MPG's if all of them drive basically the same? A coworker of mine up in Maryland, he has a 5.9 4x4 3:92 gear ratio and he averages 19-21 mpg on highway!!! If I can get 18 mpg hwy, I will start driving my durango more often!