1993 Dakota, 3.9L V6 Horrible Gas Mileage
#1
1993 Dakota, 3.9L V6 Horrible Gas Mileage
Greetings:
Am new the forum, and also a new Dakota owner. Purchased a Dakota (specs below) for a little of nothing ($100) that runs, and have been slowly doing a bit of maintenance here and there to it. It's not my primary transportation, I mainly bought it to haul stuff with.
However, I have noticed that it's getting pretty horrible gas mileage. Somewhere around 9-10 MPG highway, which even with the 3.9L V6, I should be getting well above that. Voltage is strong, and so is oil pressure, except when sitting at a stop light, where it almost bottoms out.
There's no loss of power and idles well, although the engine ticks/knocks pretty bad when accelerating. It's obvious that little, if any, maintenance was done to the truck before I purchased it.
All I've done so far is basic maintenance: oil change (totally black), spark plug change (looks like it was running hot from the spark plugs as some were white, and the rest were black/fouled), air filter, fuel filter, and PCV valve. Basically the cheap stuff. When I checked the coolant level, it took 2 gallons to bring it up to a visible level, and the overflow was bone dry.
Before moving forward, I'd just like some general suggestions. My thoughts are a possible O2 sensor issue, or EGR valve ... any other thoughts on a truck this old?
Haven't run codes yet, but I'll try to do that tonight and amend the post.
Am new the forum, and also a new Dakota owner. Purchased a Dakota (specs below) for a little of nothing ($100) that runs, and have been slowly doing a bit of maintenance here and there to it. It's not my primary transportation, I mainly bought it to haul stuff with.
However, I have noticed that it's getting pretty horrible gas mileage. Somewhere around 9-10 MPG highway, which even with the 3.9L V6, I should be getting well above that. Voltage is strong, and so is oil pressure, except when sitting at a stop light, where it almost bottoms out.
There's no loss of power and idles well, although the engine ticks/knocks pretty bad when accelerating. It's obvious that little, if any, maintenance was done to the truck before I purchased it.
All I've done so far is basic maintenance: oil change (totally black), spark plug change (looks like it was running hot from the spark plugs as some were white, and the rest were black/fouled), air filter, fuel filter, and PCV valve. Basically the cheap stuff. When I checked the coolant level, it took 2 gallons to bring it up to a visible level, and the overflow was bone dry.
Before moving forward, I'd just like some general suggestions. My thoughts are a possible O2 sensor issue, or EGR valve ... any other thoughts on a truck this old?
Haven't run codes yet, but I'll try to do that tonight and amend the post.
- 1993 Dodge Dakota LE Extended Cab
- 243,000 miles
- 3.9L MPFI 180HP 225TQ
- 22 Gallon Tank
- 2WD, Automatic Transmission
- Factory Towing/Overdrive Cutout
- White Paint (peeling ... defective primer?)
#3
Welcome! You got my Dakota! I have about the exact truck, and let me tell you - it is the BEST vehicle I have EVER had - any kind! And, I have been driving since about 1965! Mine had 43,000 miles when I bought it in 1997, and odometer broke at 120,xxx miles about 8 years ago. Crazy (above) is probably right about the O2 or EGR. Anyway, I think you got a pretty good deal!
#4
i was gunna suggest the o2 sensor as well my old 91 used to get about 80 miles to the tank and blew out black smoke when i floored it i never changed it cuz i liked the james bond option for tailgaters on the highway the egr is a good point too. im not getting great milage with my 96 5.2 either i guess i too will try to change these two things.
#5
Thanks for the welcomes and tips. O2 first it is, then, and then I'll check the EGR. That was my thoughts, I just know the O2 can be a major pain to get out on older trucks like this, so I just wanted to confirm before I started work on it.
All in all, it's a great truck, except for the gas mileage and paint peeling issue. Just looks like he finally decided to stop doing maintenance on it and just drove it until he felt it was falling apart. Probably do an engine and coolant system flush after I get the O2 and EGR changed out and then work on a major tune up over a couple of weekends.
Thanks all!
All in all, it's a great truck, except for the gas mileage and paint peeling issue. Just looks like he finally decided to stop doing maintenance on it and just drove it until he felt it was falling apart. Probably do an engine and coolant system flush after I get the O2 and EGR changed out and then work on a major tune up over a couple of weekends.
Thanks all!
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Miles per tank doesn't mean anything. The gas gauge and tank size are irrelevant and inaccurate in determining MPG. The only thing that matters is miles driven divided by gallons used, i.e; fill the tank, drive 100-200 miles, fill up again, the gallons it takes divided by the miles you drove is your MPG.