I just bought a 2003 SXT club cab Dakota 4x4 with a 3.9L in it. This beast sucks fuel down like flushing a toilet. Is there anything that can be done to help this situation out any. This is my 4th Dakota. My 88 4x4 I had got 15-18 driving with 215000 on the odometer. My 01 2 wheel drive got as good as 22 mpg on the highway with a 3.9l in it. Is there anything I can do or check to help out this fuel usage. This truck has 62,000 miles on it. Any positive input will be highly appreciated.. Thanks Kelly

 

I have the same problem, when I bought my truck with 123,000 on it I could pull a trailer going 65 and get 20 mpg now I think I get like 17 or 18 now that it is about 197,000 miles. Mine is the 3.9 as well, I've replaced the cap, rotor, plugs, and wires. I've put in a K&N air filter and replaced the thermostat. I have just recently striaght piped it as well.

 

Try doing a complete tune up. I know my truck was bad at 80k I gained 2mpg. I was only getting 10 then a tune up took me to 12 now with intake and tuner I can squeeze 15-16 out of her.

 

I am assuming plugs,wires,cap and rotor. What brand are you using? Also what kind of intake and tuner are you using also? Thanks Kelly

 

I am using autolite 3923's plugs and duralast gold cap,rotor and wires. My intake is just a cheap one off ebay(no sense of paying for the name when its the same thing) and a Sct tuner from hemifever. I run the 93 tune(highest) with 89 gas.

 

Well I think I have figured out my issue with the fuel usage. I just bought this truck from a dealer 2 days ago and was supposed to be all serviced. While checking thinks out today I noticed the oil on the dipstick was 2 1/2 to 3" above the full mark. Must be the wingnut service guy thought he drained the oil and just put more in. Lucky the engine didn't blow up. I am taking it back to the service department in the morning and have it corrected. The crank must have been almost completely submerged in oil. I am hoping the motor was not damaged in any way. Keep everyone posted on the outcome.

 

A quart overfilled wont hurt anything but any more than that and you could be in trouble.

 

There was like 6 qts in the crankcase when I took it back to have the dealer change it. Got the plugs,wires, dist cap and rotor changed yesterday also. The plugs had almost 150 thou gap on them. Original plugs and were worn. The rotor was burnt back more than an 1/8". The plug wires had some dry cracking on them. Needless to say I am very pleased with the outcome. I am getting respectable gas mileage now. Thanks dodgeramguy85. Kelly

 

Yeah no problem. Glad to hear you got it all taken care of!

 

Among the other things I had mentioned I found the tire pressures all at 30psi. Boosted them all up to 35psi and installed a home made cold air set up on it. Forgot I had a 10' piece of 3" polished stainless tubing squirreled away in the garage. Cut off 18" chunk and stuck a 3" ID filter on the end of the pipe and stuck the other end of the pipe in the flexible hose from the air horn and hosed clamped. Viola a less than $25 cold air set up.