Hi all, have some questions, here is the info:
2003 Dodge Dakota 4x4 Sport Plus 4.7L Magnum.
70,000 miles
I used to average 16mpg combined City/Hwy
Over the last year it went down to 11.4
A few years ago I did replace the factory tires with the next largest, P265/R16
Last month I put in a K&N cold air intake. Combined mpg is now 12.6 (so up 1 mpg).
Truck also seems to lack get up and go, power, seems weak. I have to floor it and then it downshifts and "sorta" moves.
My goal is to fix the fuel economy problem and get the truck running good again. If I can get a little more HP for the $$ that is great but I am not looking to dump big $$ for little gains.

Scouring this forum and others, I've compiled a list of possible things to try and I have some questions:
1. Sea foam in gas and oil
2. Spark plugs, put in Autolite 3923's
The Autolite website does not list these for my truck, did I get the number wrong? What specific part number do you recommend?
3. Wires, cap, rotar
Are the more expensive performance sets worth it?
Can you recommend some specific part numbers?
4. Change tranny fluid - I have not changed this so it still has the 5-45RFE
Is this worth it and if so, what specific fluid do you recommend?
5. Replace the MAP sensor
Anyone have a recommended part number?
6. Exhaust - here is where I would spend a little money because the factory exhaust is in need of replacement anyway. Any recommendations on an exhaust kit that will fit my truck, maybe give it a little growl (not a rap, I don't want the rapping sound).

So, any other recommendations? Things I missed? Things from my list that are not worth it?

Thanks in advance everyone, I actually look forward to tinking around with the recommendations you have and seeing some results. I am learning about vehicles slowly but surely.
Jeff

 

you are spot on. change the plugs, and runs some seafoam, just a basic tune up.

 

Hi Jeff,

Welcome to the forums.

You can skip #3. There are no wires, cap, or rotor on a 4.7.

Spark plugs - everyone has ideas about what's best. I'd put the stock Champions back in. RC12mcc4's.

I'd probably look at the 02 sensors too. They should throw a code but can make your mileage drop like crazy when they fail.

Does it feel like the transmission is slipping?

 

Thanks for the fast replies!

DakDan, what I have noticed about the tranny:
1. Sometimes when I put it in reverse, it does not actually go into reverse. Truck just sits there. I have to put it back in Park and then back into reverse. Doesn't happen often.
2. Sometimes the tranny seems a little loud when I shift between Park and Drive. A bit of a clunk. Could be normal and not that loud at all cause I'm no vehicle expert.
So I don't think of slipping....maybe more sluggish.

 

is the fluid full/dirty?

as for exhaust, just replace the muffler, get on youtube and search for exhaust clips, find one you like.

 

Yes there is 3923's thats what im running in my truck. Look on youtube for different exhaust ideas. I loved my magnaflow when I had it on. Pretty much just tune up stuff 1,2,4 and 5. Also getting a tuner will help restore power.

Here is mine. Sounds better if viewing on something with a good sound system.Also it was only 2 months old so wasnt fully broken in yet.
http://www.youtube.com/watch?v=C5q3QtdxVpM

 

I'd add a transmission fluid/filter change. If it hasn't been done then it can't hurt.

 

I would change the fluid in your differentials, and your transfer case as well.

 

Might wanna try freshening up the O2 sensors for better milage as well.

I suggest Denso brand sensors.

The 3923's are for the 5.9, 5.2, and 3.9 magnums. The 4.7 does NOT have distributor cap, rotor or wires, it has a coil on each plug. So this stuff isnt needed.

 

After reading different threads on this forum about the MAP sensor, I changed mine a few months ago. It was the best $90 I have spent on my truck. I have the 3.9 but some of the motors take a cheaper MAP sensor. I recommend doing a search and read some of the threads on this subject. Good luck.