What modifications are recomanded to improve overall performance ane fuel economy on a 2003 Dodge Ram, 5.9 cummins, auto trans, 4x4, 140K miles , quad cab, long box, ? Not crazy about the auto transmission but its priced right !

It will be used to pull a three horse goose neck with weekend package as well as daily comuter

FINALLY GOT MY POST TO PRINT !

Well here is what I have done and works well in my opinion.  The 03 and early 04 are the best out of the 03 to 07 5.9 truck for fuel mileage.  Since that truck is a 4x4 you more than likely have the HO motor and will be 305hp instead of 285hp so with the following upgrades you really should not need anything else for a good running truck.

1st, free flowing exhaust system.  There is no need to spend high dollar buying aftermark stuff as long as you have a local muffler shop they can do about the same thing cheaper.  Get them to run a 4" pipe from the downpipe back (most 03 up Dodges already have a 4" tailpipe.

2nd, Aftermarket intake kit is a must!  I was using K&N, but now gone to S&B because it is more of an inclose unit and keeps most of the engine heat out of the intake but really makes these Cummins engine breath!

If you end up wanting more HP and alittle more fuel mileage there is a couple of good options for these truck that work really well.  H&S Performance (this is one I have on my 07.5 Dodge) and Smarty both are actual programmers and do have adjustments for auto trannys, adjustments for different size tires and a code reader all in one unit.

If you are happy with the power I would do the air and exhaust then drive it before spending any more money.

can't speak for the new ones or the mods----

I have a beat up 1997 Dodge 2500 5.9L Cummins totally stock w/ 245,000 miles on it and the ol' hoss runs like a bastard. I keep it serviced, oil changes, filter changes, valve adjustments at all recommended intervals. I typically tow about 7,000 lb trailer---but loaded with hay I can be around 10k ....without complaints---when I get on it, it get's down and goes. 22mpg cruising empty 17mpg towing

I'd get the loaded weight of the trailer you intend to tow and check your GCVWR on the truck, you can go over your GCVWR but it will give you an idea of how hard the truck would be working for you. I have a feeling you'll be Ok unless you have a LQ or something, that truck will tow it, it's just bigger trailers the 1 ton dually and biggger engine give you a little easier time and less wear and tear on the vehicle

....IMO as far as performance and mileage.....you'll move the trailer fine and get decent milage if you go easy on the pedal.

Just start with the simple things I listed above, then if you need something else you can PM me or call me and I can help you out. 

My cell number is 817-903-1048

Dodge and Ford DIESEL trucks is about all I deal with everyday!  If you buying an older 2000, 01 or 02 truck I think I still have an EDGE module you could try out.

Not at all.

Depending on your local laws now.....  I would run it without the cat for sure.  Most diesel trucks before the DPF grap in 07/08 and newer do have to have the cat to pass inspection.

The muffler is up to you, I never run them on any of my diesels.  The only one I would have use a muffle on was a 2005 Dodge I have and some reason it was LOUD, but the others was not that bad.

What ever you do get your muffler shop to let you keep your cat (if yours has one) just in case.  If you think you need a muffler buy on off of ebay. (i will send you some info on ones that worl good).

I am running my 07.5 with the 6.7 engine with NO DPF and NO muffler and it actually sounds like the older 5.9's (nice deep tone).

I just noticed your from up north (way up north) and there is a few great diesel shop up there.(will send that info too)

Here is one of the largest in your part of the country.  Not sure how far they are from you, but you can call them and they will help you find small shops closer to you.  Plus they sell all types of parts for diesel trucks.

North American Diesel Performance
12836-151 Street
Edmonton, Alberta
T5V-1G8

Phone: (780) 456-4498
Toll Free: (866) 456-4498
Email: info@nadp.ca

Still waiting on replies for the test on diesels.  The guys can more than likely help with that too.  Will let you know when I get a reply.