I keep reading in several different forums of these guys that get close to and sometimes over 20 miles per gallon in the dakota with the 3.9 V6 4x4 Ext cab. I have a 96 Dakota with 158,000 on it and since I have had it which has been about a year. I dont get any where near that I would be very happy with 18mpg. I just wonder if these guys have an accurate or close to accurate way of reading the mpg. I know with certain mods like the injector synching, crank sensor mod, CAI etc it should help but I cant help but notice that so far everything I have done has still only yeilded me 12-13 and I live in a rural place all my driving is avg 45 mph no real stop and go at all. I did change the rear gears from a 3.92 to a 3.55 because when I bought the truck the front diff was destroyed and all I could find in the junkyards were the 3.55's which for my driving is better anyway. This brings me to a question would changing those gears affect my speedo at all? Or my trip? I have 215/70/15's on the truck and I got it with 235/75/15's. Is it something I did?

 

I was getting 13 mpg. I added the Jet stage 3 performance chip, and changed out my o2 sensor. I jumped up to 20 mpg, and leveled out at 17 average mpg. I drive em like I stole em though.

 

is there any real power response from that jet chip? I figure there must be since if your mileage jumps up that far but did you do the o2 sensor at the same time? I know a bad o2 sensor can give crappy mileage. Which one did you change? the upstream (before cat) or downstream (after Cat)?

 

wheres all these people getting 20mpg with the 3.9 4x4 ? because i dont see it happening especially if you got the live front axle. aint no way ill believe until i see hard evidence. hek my '04 tacoma 3.4l 4x4 wont even get 20mph and its alot newer technology

 

They are around and I had my front differential out for a couple months I just had the cv joint caps in so I can drive it and keep the wheels on lol and I still got crap mileage. I def agree that the live axle did decrease the mileage but not by too much after I installed everything again. I just ordered a denso upstream sensor as the truck does have 158K on it and im pretty sure its overdue and that sensor should make some change in mpg as long as everything else is ok.

 

not sure if I can post links here but look at these posts just a few i have seen this to me is good mileage with the 4x4. there are a couple 3.9 mpg posts

http://www.dodgedakotas.com/boards/v6/12437.html

 

I wouldn't want the v6 without that chip. It was a huge difference to me. I did a bunch of things all around the same time, so not sure what was the biggest help. The chip gained 2-3 mpg. And it was the o2 sensor before the cat I believe. Mine only had 1 o2 sensor. You must have the '96 OBD2? I was getting lean or rich codes, and o2 sensor codes. None of which ever gave me a CEL. If my truck hadn't been abused before my ownership, It would have no problem hitting 20 mpg.

 

I have a 92 Dakota club cab 4x4 with stick shift. I always reset my trip when I fill up and calculate my mileage by the miles on the trip divided by how much gas I have to put in. My driving is probably 60% highway and 40%town; and I roughly average 17.5 mpg.

 

Yes it will affect the speedo. Get a GPS and see how far off it is. Most smart phones can show your speed.

 

Yes I have the 96 no EGR and it is OBD2, 2 Oxygen Sensors I ordered the Precat O2 sensor last night as I am pretty sure that is the one that affects the A/F ratio and prob has never been changed although I dont have a CEL on I know they can become lazy and not trip a code I got the Denso One Ill install that and see what happens.

I guess I will have to invest in a GPS I do have a smartphone but the route I travel everday has a pretty good area of no coverage. Would you have any idea on how much (around about Figure) it would throw off the sensor I have tried to search and I dont really find anything on that subject that I can grasp.